* [PATCH v2] x86/kexec: Merge x86_32 and x86_64 code using macros from asm.h @ 2025-03-06 14:52 Uros Bizjak 2025-03-06 21:33 ` [tip: x86/asm] x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> tip-bot2 for Uros Bizjak 2025-03-19 11:03 ` [tip: x86/core] " tip-bot2 for Uros Bizjak 0 siblings, 2 replies; 6+ messages in thread From: Uros Bizjak @ 2025-03-06 14:52 UTC (permalink / raw) To: x86, linux-kernel Cc: Uros Bizjak, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin Merge common x86_32 and x86_64 code in crash_setup_regs() using macros from asm/asm.h. The compiled object files before and after the patch are unchanged. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> --- v2: Remove size suffixes from instructions. --- arch/x86/include/asm/kexec.h | 58 ++++++++++++++++-------------------- 1 file changed, 25 insertions(+), 33 deletions(-) diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h index 8ad187462b68..e3589d6aec24 100644 --- a/arch/x86/include/asm/kexec.h +++ b/arch/x86/include/asm/kexec.h @@ -18,6 +18,7 @@ #include <linux/string.h> #include <linux/kernel.h> +#include <asm/asm.h> #include <asm/page.h> #include <asm/ptrace.h> @@ -71,41 +72,32 @@ static inline void crash_setup_regs(struct pt_regs *newregs, if (oldregs) { memcpy(newregs, oldregs, sizeof(*newregs)); } else { + asm volatile("mov %%" _ASM_BX ",%0" : "=m"(newregs->bx)); + asm volatile("mov %%" _ASM_CX ",%0" : "=m"(newregs->cx)); + asm volatile("mov %%" _ASM_DX ",%0" : "=m"(newregs->dx)); + asm volatile("mov %%" _ASM_SI ",%0" : "=m"(newregs->si)); + asm volatile("mov %%" _ASM_DI ",%0" : "=m"(newregs->di)); + asm volatile("mov %%" _ASM_BP ",%0" : "=m"(newregs->bp)); + asm volatile("mov %%" _ASM_AX ",%0" : "=m"(newregs->ax)); + asm volatile("mov %%" _ASM_SP ",%0" : "=m"(newregs->sp)); +#ifdef CONFIG_X86_64 + asm volatile("mov %%r8,%0" : "=m"(newregs->r8)); + asm volatile("mov %%r9,%0" : "=m"(newregs->r9)); + asm volatile("mov %%r10,%0" : "=m"(newregs->r10)); + asm volatile("mov %%r11,%0" : "=m"(newregs->r11)); + asm volatile("mov %%r12,%0" : "=m"(newregs->r12)); + asm volatile("mov %%r13,%0" : "=m"(newregs->r13)); + asm volatile("mov %%r14,%0" : "=m"(newregs->r14)); + asm volatile("mov %%r15,%0" : "=m"(newregs->r15)); +#endif + asm volatile("mov %%ss,%k0" : "=a"(newregs->ss)); + asm volatile("mov %%cs,%k0" : "=a"(newregs->cs)); #ifdef CONFIG_X86_32 - asm volatile("movl %%ebx,%0" : "=m"(newregs->bx)); - asm volatile("movl %%ecx,%0" : "=m"(newregs->cx)); - asm volatile("movl %%edx,%0" : "=m"(newregs->dx)); - asm volatile("movl %%esi,%0" : "=m"(newregs->si)); - asm volatile("movl %%edi,%0" : "=m"(newregs->di)); - asm volatile("movl %%ebp,%0" : "=m"(newregs->bp)); - asm volatile("movl %%eax,%0" : "=m"(newregs->ax)); - asm volatile("movl %%esp,%0" : "=m"(newregs->sp)); - asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); - asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); - asm volatile("movl %%ds, %%eax;" :"=a"(newregs->ds)); - asm volatile("movl %%es, %%eax;" :"=a"(newregs->es)); - asm volatile("pushfl; popl %0" :"=m"(newregs->flags)); -#else - asm volatile("movq %%rbx,%0" : "=m"(newregs->bx)); - asm volatile("movq %%rcx,%0" : "=m"(newregs->cx)); - asm volatile("movq %%rdx,%0" : "=m"(newregs->dx)); - asm volatile("movq %%rsi,%0" : "=m"(newregs->si)); - asm volatile("movq %%rdi,%0" : "=m"(newregs->di)); - asm volatile("movq %%rbp,%0" : "=m"(newregs->bp)); - asm volatile("movq %%rax,%0" : "=m"(newregs->ax)); - asm volatile("movq %%rsp,%0" : "=m"(newregs->sp)); - asm volatile("movq %%r8,%0" : "=m"(newregs->r8)); - asm volatile("movq %%r9,%0" : "=m"(newregs->r9)); - asm volatile("movq %%r10,%0" : "=m"(newregs->r10)); - asm volatile("movq %%r11,%0" : "=m"(newregs->r11)); - asm volatile("movq %%r12,%0" : "=m"(newregs->r12)); - asm volatile("movq %%r13,%0" : "=m"(newregs->r13)); - asm volatile("movq %%r14,%0" : "=m"(newregs->r14)); - asm volatile("movq %%r15,%0" : "=m"(newregs->r15)); - asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); - asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); - asm volatile("pushfq; popq %0" :"=m"(newregs->flags)); + asm volatile("mov %%ds,%k0" : "=a"(newregs->ds)); + asm volatile("mov %%es,%k0" : "=a"(newregs->es)); #endif + asm volatile("pushf\n\t" + "pop %0" : "=m"(newregs->flags)); newregs->ip = _THIS_IP_; } } -- 2.48.1 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [tip: x86/asm] x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> 2025-03-06 14:52 [PATCH v2] x86/kexec: Merge x86_32 and x86_64 code using macros from asm.h Uros Bizjak @ 2025-03-06 21:33 ` tip-bot2 for Uros Bizjak 2025-03-07 3:00 ` H. Peter Anvin 2025-03-19 11:03 ` [tip: x86/core] " tip-bot2 for Uros Bizjak 1 sibling, 1 reply; 6+ messages in thread From: tip-bot2 for Uros Bizjak @ 2025-03-06 21:33 UTC (permalink / raw) To: linux-tip-commits Cc: Uros Bizjak, Ingo Molnar, David Woodhouse, Baoquan He, Vivek Goyal, Dave Young, Ard Biesheuvel, H. Peter Anvin, x86, linux-kernel The following commit has been merged into the x86/asm branch of tip: Commit-ID: aa3942d4d12ef57f031faa2772fe410c24191e36 Gitweb: https://git.kernel.org/tip/aa3942d4d12ef57f031faa2772fe410c24191e36 Author: Uros Bizjak <ubizjak@gmail.com> AuthorDate: Thu, 06 Mar 2025 15:52:11 +01:00 Committer: Ingo Molnar <mingo@kernel.org> CommitterDate: Thu, 06 Mar 2025 22:04:48 +01:00 x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> Merge common x86_32 and x86_64 code in crash_setup_regs() using macros from <asm/asm.h>. The compiled object files before and after the patch are unchanged. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lore.kernel.org/r/20250306145227.55819-1-ubizjak@gmail.com --- arch/x86/include/asm/kexec.h | 58 +++++++++++++++-------------------- 1 file changed, 25 insertions(+), 33 deletions(-) diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h index 8ad1874..e3589d6 100644 --- a/arch/x86/include/asm/kexec.h +++ b/arch/x86/include/asm/kexec.h @@ -18,6 +18,7 @@ #include <linux/string.h> #include <linux/kernel.h> +#include <asm/asm.h> #include <asm/page.h> #include <asm/ptrace.h> @@ -71,41 +72,32 @@ static inline void crash_setup_regs(struct pt_regs *newregs, if (oldregs) { memcpy(newregs, oldregs, sizeof(*newregs)); } else { + asm volatile("mov %%" _ASM_BX ",%0" : "=m"(newregs->bx)); + asm volatile("mov %%" _ASM_CX ",%0" : "=m"(newregs->cx)); + asm volatile("mov %%" _ASM_DX ",%0" : "=m"(newregs->dx)); + asm volatile("mov %%" _ASM_SI ",%0" : "=m"(newregs->si)); + asm volatile("mov %%" _ASM_DI ",%0" : "=m"(newregs->di)); + asm volatile("mov %%" _ASM_BP ",%0" : "=m"(newregs->bp)); + asm volatile("mov %%" _ASM_AX ",%0" : "=m"(newregs->ax)); + asm volatile("mov %%" _ASM_SP ",%0" : "=m"(newregs->sp)); +#ifdef CONFIG_X86_64 + asm volatile("mov %%r8,%0" : "=m"(newregs->r8)); + asm volatile("mov %%r9,%0" : "=m"(newregs->r9)); + asm volatile("mov %%r10,%0" : "=m"(newregs->r10)); + asm volatile("mov %%r11,%0" : "=m"(newregs->r11)); + asm volatile("mov %%r12,%0" : "=m"(newregs->r12)); + asm volatile("mov %%r13,%0" : "=m"(newregs->r13)); + asm volatile("mov %%r14,%0" : "=m"(newregs->r14)); + asm volatile("mov %%r15,%0" : "=m"(newregs->r15)); +#endif + asm volatile("mov %%ss,%k0" : "=a"(newregs->ss)); + asm volatile("mov %%cs,%k0" : "=a"(newregs->cs)); #ifdef CONFIG_X86_32 - asm volatile("movl %%ebx,%0" : "=m"(newregs->bx)); - asm volatile("movl %%ecx,%0" : "=m"(newregs->cx)); - asm volatile("movl %%edx,%0" : "=m"(newregs->dx)); - asm volatile("movl %%esi,%0" : "=m"(newregs->si)); - asm volatile("movl %%edi,%0" : "=m"(newregs->di)); - asm volatile("movl %%ebp,%0" : "=m"(newregs->bp)); - asm volatile("movl %%eax,%0" : "=m"(newregs->ax)); - asm volatile("movl %%esp,%0" : "=m"(newregs->sp)); - asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); - asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); - asm volatile("movl %%ds, %%eax;" :"=a"(newregs->ds)); - asm volatile("movl %%es, %%eax;" :"=a"(newregs->es)); - asm volatile("pushfl; popl %0" :"=m"(newregs->flags)); -#else - asm volatile("movq %%rbx,%0" : "=m"(newregs->bx)); - asm volatile("movq %%rcx,%0" : "=m"(newregs->cx)); - asm volatile("movq %%rdx,%0" : "=m"(newregs->dx)); - asm volatile("movq %%rsi,%0" : "=m"(newregs->si)); - asm volatile("movq %%rdi,%0" : "=m"(newregs->di)); - asm volatile("movq %%rbp,%0" : "=m"(newregs->bp)); - asm volatile("movq %%rax,%0" : "=m"(newregs->ax)); - asm volatile("movq %%rsp,%0" : "=m"(newregs->sp)); - asm volatile("movq %%r8,%0" : "=m"(newregs->r8)); - asm volatile("movq %%r9,%0" : "=m"(newregs->r9)); - asm volatile("movq %%r10,%0" : "=m"(newregs->r10)); - asm volatile("movq %%r11,%0" : "=m"(newregs->r11)); - asm volatile("movq %%r12,%0" : "=m"(newregs->r12)); - asm volatile("movq %%r13,%0" : "=m"(newregs->r13)); - asm volatile("movq %%r14,%0" : "=m"(newregs->r14)); - asm volatile("movq %%r15,%0" : "=m"(newregs->r15)); - asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); - asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); - asm volatile("pushfq; popq %0" :"=m"(newregs->flags)); + asm volatile("mov %%ds,%k0" : "=a"(newregs->ds)); + asm volatile("mov %%es,%k0" : "=a"(newregs->es)); #endif + asm volatile("pushf\n\t" + "pop %0" : "=m"(newregs->flags)); newregs->ip = _THIS_IP_; } } ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [tip: x86/asm] x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> 2025-03-06 21:33 ` [tip: x86/asm] x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> tip-bot2 for Uros Bizjak @ 2025-03-07 3:00 ` H. Peter Anvin 2025-03-07 9:20 ` Uros Bizjak 0 siblings, 1 reply; 6+ messages in thread From: H. Peter Anvin @ 2025-03-07 3:00 UTC (permalink / raw) To: linux-kernel, tip-bot2 for Uros Bizjak, linux-tip-commits Cc: Uros Bizjak, Ingo Molnar, David Woodhouse, Baoquan He, Vivek Goyal, Dave Young, Ard Biesheuvel, x86 On March 6, 2025 1:33:43 PM PST, tip-bot2 for Uros Bizjak <tip-bot2@linutronix.de> wrote: >The following commit has been merged into the x86/asm branch of tip: > >Commit-ID: aa3942d4d12ef57f031faa2772fe410c24191e36 >Gitweb: https://git.kernel.org/tip/aa3942d4d12ef57f031faa2772fe410c24191e36 >Author: Uros Bizjak <ubizjak@gmail.com> >AuthorDate: Thu, 06 Mar 2025 15:52:11 +01:00 >Committer: Ingo Molnar <mingo@kernel.org> >CommitterDate: Thu, 06 Mar 2025 22:04:48 +01:00 > >x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> > >Merge common x86_32 and x86_64 code in crash_setup_regs() >using macros from <asm/asm.h>. > >The compiled object files before and after the patch are unchanged. > >Signed-off-by: Uros Bizjak <ubizjak@gmail.com> >Signed-off-by: Ingo Molnar <mingo@kernel.org> >Cc: David Woodhouse <dwmw@amazon.co.uk> >Cc: Baoquan He <bhe@redhat.com> >Cc: Vivek Goyal <vgoyal@redhat.com> >Cc: Dave Young <dyoung@redhat.com> >Cc: Ard Biesheuvel <ardb@kernel.org> >Cc: "H. Peter Anvin" <hpa@zytor.com> >Link: https://lore.kernel.org/r/20250306145227.55819-1-ubizjak@gmail.com >--- > arch/x86/include/asm/kexec.h | 58 +++++++++++++++-------------------- > 1 file changed, 25 insertions(+), 33 deletions(-) > >diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h >index 8ad1874..e3589d6 100644 >--- a/arch/x86/include/asm/kexec.h >+++ b/arch/x86/include/asm/kexec.h >@@ -18,6 +18,7 @@ > #include <linux/string.h> > #include <linux/kernel.h> > >+#include <asm/asm.h> > #include <asm/page.h> > #include <asm/ptrace.h> > >@@ -71,41 +72,32 @@ static inline void crash_setup_regs(struct pt_regs *newregs, > if (oldregs) { > memcpy(newregs, oldregs, sizeof(*newregs)); > } else { >+ asm volatile("mov %%" _ASM_BX ",%0" : "=m"(newregs->bx)); >+ asm volatile("mov %%" _ASM_CX ",%0" : "=m"(newregs->cx)); >+ asm volatile("mov %%" _ASM_DX ",%0" : "=m"(newregs->dx)); >+ asm volatile("mov %%" _ASM_SI ",%0" : "=m"(newregs->si)); >+ asm volatile("mov %%" _ASM_DI ",%0" : "=m"(newregs->di)); >+ asm volatile("mov %%" _ASM_BP ",%0" : "=m"(newregs->bp)); >+ asm volatile("mov %%" _ASM_AX ",%0" : "=m"(newregs->ax)); >+ asm volatile("mov %%" _ASM_SP ",%0" : "=m"(newregs->sp)); >+#ifdef CONFIG_X86_64 >+ asm volatile("mov %%r8,%0" : "=m"(newregs->r8)); >+ asm volatile("mov %%r9,%0" : "=m"(newregs->r9)); >+ asm volatile("mov %%r10,%0" : "=m"(newregs->r10)); >+ asm volatile("mov %%r11,%0" : "=m"(newregs->r11)); >+ asm volatile("mov %%r12,%0" : "=m"(newregs->r12)); >+ asm volatile("mov %%r13,%0" : "=m"(newregs->r13)); >+ asm volatile("mov %%r14,%0" : "=m"(newregs->r14)); >+ asm volatile("mov %%r15,%0" : "=m"(newregs->r15)); >+#endif >+ asm volatile("mov %%ss,%k0" : "=a"(newregs->ss)); >+ asm volatile("mov %%cs,%k0" : "=a"(newregs->cs)); > #ifdef CONFIG_X86_32 >- asm volatile("movl %%ebx,%0" : "=m"(newregs->bx)); >- asm volatile("movl %%ecx,%0" : "=m"(newregs->cx)); >- asm volatile("movl %%edx,%0" : "=m"(newregs->dx)); >- asm volatile("movl %%esi,%0" : "=m"(newregs->si)); >- asm volatile("movl %%edi,%0" : "=m"(newregs->di)); >- asm volatile("movl %%ebp,%0" : "=m"(newregs->bp)); >- asm volatile("movl %%eax,%0" : "=m"(newregs->ax)); >- asm volatile("movl %%esp,%0" : "=m"(newregs->sp)); >- asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); >- asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); >- asm volatile("movl %%ds, %%eax;" :"=a"(newregs->ds)); >- asm volatile("movl %%es, %%eax;" :"=a"(newregs->es)); >- asm volatile("pushfl; popl %0" :"=m"(newregs->flags)); >-#else >- asm volatile("movq %%rbx,%0" : "=m"(newregs->bx)); >- asm volatile("movq %%rcx,%0" : "=m"(newregs->cx)); >- asm volatile("movq %%rdx,%0" : "=m"(newregs->dx)); >- asm volatile("movq %%rsi,%0" : "=m"(newregs->si)); >- asm volatile("movq %%rdi,%0" : "=m"(newregs->di)); >- asm volatile("movq %%rbp,%0" : "=m"(newregs->bp)); >- asm volatile("movq %%rax,%0" : "=m"(newregs->ax)); >- asm volatile("movq %%rsp,%0" : "=m"(newregs->sp)); >- asm volatile("movq %%r8,%0" : "=m"(newregs->r8)); >- asm volatile("movq %%r9,%0" : "=m"(newregs->r9)); >- asm volatile("movq %%r10,%0" : "=m"(newregs->r10)); >- asm volatile("movq %%r11,%0" : "=m"(newregs->r11)); >- asm volatile("movq %%r12,%0" : "=m"(newregs->r12)); >- asm volatile("movq %%r13,%0" : "=m"(newregs->r13)); >- asm volatile("movq %%r14,%0" : "=m"(newregs->r14)); >- asm volatile("movq %%r15,%0" : "=m"(newregs->r15)); >- asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); >- asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); >- asm volatile("pushfq; popq %0" :"=m"(newregs->flags)); >+ asm volatile("mov %%ds,%k0" : "=a"(newregs->ds)); >+ asm volatile("mov %%es,%k0" : "=a"(newregs->es)); > #endif >+ asm volatile("pushf\n\t" >+ "pop %0" : "=m"(newregs->flags)); > newregs->ip = _THIS_IP_; > } > } Incidentally, doing this in C code is obviously completely broken, especially doing it in multiple statements. You have no idea what the compiler has messed with before you get there. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [tip: x86/asm] x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> 2025-03-07 3:00 ` H. Peter Anvin @ 2025-03-07 9:20 ` Uros Bizjak 2025-03-07 11:13 ` H. Peter Anvin 0 siblings, 1 reply; 6+ messages in thread From: Uros Bizjak @ 2025-03-07 9:20 UTC (permalink / raw) To: H. Peter Anvin Cc: linux-kernel, tip-bot2 for Uros Bizjak, linux-tip-commits, Ingo Molnar, David Woodhouse, Baoquan He, Vivek Goyal, Dave Young, Ard Biesheuvel, x86 On Fri, Mar 7, 2025 at 4:00 AM H. Peter Anvin <hpa@zytor.com> wrote: > > On March 6, 2025 1:33:43 PM PST, tip-bot2 for Uros Bizjak <tip-bot2@linutronix.de> wrote: > >The following commit has been merged into the x86/asm branch of tip: > > > >Commit-ID: aa3942d4d12ef57f031faa2772fe410c24191e36 > >Gitweb: https://git.kernel.org/tip/aa3942d4d12ef57f031faa2772fe410c24191e36 > >Author: Uros Bizjak <ubizjak@gmail.com> > >AuthorDate: Thu, 06 Mar 2025 15:52:11 +01:00 > >Committer: Ingo Molnar <mingo@kernel.org> > >CommitterDate: Thu, 06 Mar 2025 22:04:48 +01:00 > > > >x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> > > > >Merge common x86_32 and x86_64 code in crash_setup_regs() > >using macros from <asm/asm.h>. > > > >The compiled object files before and after the patch are unchanged. > > > >Signed-off-by: Uros Bizjak <ubizjak@gmail.com> > >Signed-off-by: Ingo Molnar <mingo@kernel.org> > >Cc: David Woodhouse <dwmw@amazon.co.uk> > >Cc: Baoquan He <bhe@redhat.com> > >Cc: Vivek Goyal <vgoyal@redhat.com> > >Cc: Dave Young <dyoung@redhat.com> > >Cc: Ard Biesheuvel <ardb@kernel.org> > >Cc: "H. Peter Anvin" <hpa@zytor.com> > >Link: https://lore.kernel.org/r/20250306145227.55819-1-ubizjak@gmail.com > >--- > > arch/x86/include/asm/kexec.h | 58 +++++++++++++++-------------------- > > 1 file changed, 25 insertions(+), 33 deletions(-) > > > >diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h > >index 8ad1874..e3589d6 100644 > >--- a/arch/x86/include/asm/kexec.h > >+++ b/arch/x86/include/asm/kexec.h > >@@ -18,6 +18,7 @@ > > #include <linux/string.h> > > #include <linux/kernel.h> > > > >+#include <asm/asm.h> > > #include <asm/page.h> > > #include <asm/ptrace.h> > > > >@@ -71,41 +72,32 @@ static inline void crash_setup_regs(struct pt_regs *newregs, > > if (oldregs) { > > memcpy(newregs, oldregs, sizeof(*newregs)); > > } else { > >+ asm volatile("mov %%" _ASM_BX ",%0" : "=m"(newregs->bx)); > >+ asm volatile("mov %%" _ASM_CX ",%0" : "=m"(newregs->cx)); > >+ asm volatile("mov %%" _ASM_DX ",%0" : "=m"(newregs->dx)); > >+ asm volatile("mov %%" _ASM_SI ",%0" : "=m"(newregs->si)); > >+ asm volatile("mov %%" _ASM_DI ",%0" : "=m"(newregs->di)); > >+ asm volatile("mov %%" _ASM_BP ",%0" : "=m"(newregs->bp)); > >+ asm volatile("mov %%" _ASM_AX ",%0" : "=m"(newregs->ax)); > >+ asm volatile("mov %%" _ASM_SP ",%0" : "=m"(newregs->sp)); > >+#ifdef CONFIG_X86_64 > >+ asm volatile("mov %%r8,%0" : "=m"(newregs->r8)); > >+ asm volatile("mov %%r9,%0" : "=m"(newregs->r9)); > >+ asm volatile("mov %%r10,%0" : "=m"(newregs->r10)); > >+ asm volatile("mov %%r11,%0" : "=m"(newregs->r11)); > >+ asm volatile("mov %%r12,%0" : "=m"(newregs->r12)); > >+ asm volatile("mov %%r13,%0" : "=m"(newregs->r13)); > >+ asm volatile("mov %%r14,%0" : "=m"(newregs->r14)); > >+ asm volatile("mov %%r15,%0" : "=m"(newregs->r15)); > >+#endif > >+ asm volatile("mov %%ss,%k0" : "=a"(newregs->ss)); > >+ asm volatile("mov %%cs,%k0" : "=a"(newregs->cs)); > > #ifdef CONFIG_X86_32 > >- asm volatile("movl %%ebx,%0" : "=m"(newregs->bx)); > >- asm volatile("movl %%ecx,%0" : "=m"(newregs->cx)); > >- asm volatile("movl %%edx,%0" : "=m"(newregs->dx)); > >- asm volatile("movl %%esi,%0" : "=m"(newregs->si)); > >- asm volatile("movl %%edi,%0" : "=m"(newregs->di)); > >- asm volatile("movl %%ebp,%0" : "=m"(newregs->bp)); > >- asm volatile("movl %%eax,%0" : "=m"(newregs->ax)); > >- asm volatile("movl %%esp,%0" : "=m"(newregs->sp)); > >- asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); > >- asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); > >- asm volatile("movl %%ds, %%eax;" :"=a"(newregs->ds)); > >- asm volatile("movl %%es, %%eax;" :"=a"(newregs->es)); > >- asm volatile("pushfl; popl %0" :"=m"(newregs->flags)); > >-#else > >- asm volatile("movq %%rbx,%0" : "=m"(newregs->bx)); > >- asm volatile("movq %%rcx,%0" : "=m"(newregs->cx)); > >- asm volatile("movq %%rdx,%0" : "=m"(newregs->dx)); > >- asm volatile("movq %%rsi,%0" : "=m"(newregs->si)); > >- asm volatile("movq %%rdi,%0" : "=m"(newregs->di)); > >- asm volatile("movq %%rbp,%0" : "=m"(newregs->bp)); > >- asm volatile("movq %%rax,%0" : "=m"(newregs->ax)); > >- asm volatile("movq %%rsp,%0" : "=m"(newregs->sp)); > >- asm volatile("movq %%r8,%0" : "=m"(newregs->r8)); > >- asm volatile("movq %%r9,%0" : "=m"(newregs->r9)); > >- asm volatile("movq %%r10,%0" : "=m"(newregs->r10)); > >- asm volatile("movq %%r11,%0" : "=m"(newregs->r11)); > >- asm volatile("movq %%r12,%0" : "=m"(newregs->r12)); > >- asm volatile("movq %%r13,%0" : "=m"(newregs->r13)); > >- asm volatile("movq %%r14,%0" : "=m"(newregs->r14)); > >- asm volatile("movq %%r15,%0" : "=m"(newregs->r15)); > >- asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); > >- asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); > >- asm volatile("pushfq; popq %0" :"=m"(newregs->flags)); > >+ asm volatile("mov %%ds,%k0" : "=a"(newregs->ds)); > >+ asm volatile("mov %%es,%k0" : "=a"(newregs->es)); > > #endif > >+ asm volatile("pushf\n\t" > >+ "pop %0" : "=m"(newregs->flags)); > > newregs->ip = _THIS_IP_; > > } > > } > > Incidentally, doing this in C code is obviously completely broken, especially doing it in multiple statements. You have no idea what the compiler has messed with before you get there. These are "asm volatile" statemets, so at least they won't be scheduled in a different way. OTOH, please note that the patch is very carefully written to not change code flow, usage of hardregs in the inline asm is usually the sign of fragile code. Uros. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [tip: x86/asm] x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> 2025-03-07 9:20 ` Uros Bizjak @ 2025-03-07 11:13 ` H. Peter Anvin 0 siblings, 0 replies; 6+ messages in thread From: H. Peter Anvin @ 2025-03-07 11:13 UTC (permalink / raw) To: Uros Bizjak Cc: linux-kernel, tip-bot2 for Uros Bizjak, linux-tip-commits, Ingo Molnar, David Woodhouse, Baoquan He, Vivek Goyal, Dave Young, Ard Biesheuvel, x86 On March 7, 2025 1:20:17 AM PST, Uros Bizjak <ubizjak@gmail.com> wrote: >On Fri, Mar 7, 2025 at 4:00 AM H. Peter Anvin <hpa@zytor.com> wrote: >> >> On March 6, 2025 1:33:43 PM PST, tip-bot2 for Uros Bizjak <tip-bot2@linutronix.de> wrote: >> >The following commit has been merged into the x86/asm branch of tip: >> > >> >Commit-ID: aa3942d4d12ef57f031faa2772fe410c24191e36 >> >Gitweb: https://git.kernel.org/tip/aa3942d4d12ef57f031faa2772fe410c24191e36 >> >Author: Uros Bizjak <ubizjak@gmail.com> >> >AuthorDate: Thu, 06 Mar 2025 15:52:11 +01:00 >> >Committer: Ingo Molnar <mingo@kernel.org> >> >CommitterDate: Thu, 06 Mar 2025 22:04:48 +01:00 >> > >> >x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> >> > >> >Merge common x86_32 and x86_64 code in crash_setup_regs() >> >using macros from <asm/asm.h>. >> > >> >The compiled object files before and after the patch are unchanged. >> > >> >Signed-off-by: Uros Bizjak <ubizjak@gmail.com> >> >Signed-off-by: Ingo Molnar <mingo@kernel.org> >> >Cc: David Woodhouse <dwmw@amazon.co.uk> >> >Cc: Baoquan He <bhe@redhat.com> >> >Cc: Vivek Goyal <vgoyal@redhat.com> >> >Cc: Dave Young <dyoung@redhat.com> >> >Cc: Ard Biesheuvel <ardb@kernel.org> >> >Cc: "H. Peter Anvin" <hpa@zytor.com> >> >Link: https://lore.kernel.org/r/20250306145227.55819-1-ubizjak@gmail.com >> >--- >> > arch/x86/include/asm/kexec.h | 58 +++++++++++++++-------------------- >> > 1 file changed, 25 insertions(+), 33 deletions(-) >> > >> >diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h >> >index 8ad1874..e3589d6 100644 >> >--- a/arch/x86/include/asm/kexec.h >> >+++ b/arch/x86/include/asm/kexec.h >> >@@ -18,6 +18,7 @@ >> > #include <linux/string.h> >> > #include <linux/kernel.h> >> > >> >+#include <asm/asm.h> >> > #include <asm/page.h> >> > #include <asm/ptrace.h> >> > >> >@@ -71,41 +72,32 @@ static inline void crash_setup_regs(struct pt_regs *newregs, >> > if (oldregs) { >> > memcpy(newregs, oldregs, sizeof(*newregs)); >> > } else { >> >+ asm volatile("mov %%" _ASM_BX ",%0" : "=m"(newregs->bx)); >> >+ asm volatile("mov %%" _ASM_CX ",%0" : "=m"(newregs->cx)); >> >+ asm volatile("mov %%" _ASM_DX ",%0" : "=m"(newregs->dx)); >> >+ asm volatile("mov %%" _ASM_SI ",%0" : "=m"(newregs->si)); >> >+ asm volatile("mov %%" _ASM_DI ",%0" : "=m"(newregs->di)); >> >+ asm volatile("mov %%" _ASM_BP ",%0" : "=m"(newregs->bp)); >> >+ asm volatile("mov %%" _ASM_AX ",%0" : "=m"(newregs->ax)); >> >+ asm volatile("mov %%" _ASM_SP ",%0" : "=m"(newregs->sp)); >> >+#ifdef CONFIG_X86_64 >> >+ asm volatile("mov %%r8,%0" : "=m"(newregs->r8)); >> >+ asm volatile("mov %%r9,%0" : "=m"(newregs->r9)); >> >+ asm volatile("mov %%r10,%0" : "=m"(newregs->r10)); >> >+ asm volatile("mov %%r11,%0" : "=m"(newregs->r11)); >> >+ asm volatile("mov %%r12,%0" : "=m"(newregs->r12)); >> >+ asm volatile("mov %%r13,%0" : "=m"(newregs->r13)); >> >+ asm volatile("mov %%r14,%0" : "=m"(newregs->r14)); >> >+ asm volatile("mov %%r15,%0" : "=m"(newregs->r15)); >> >+#endif >> >+ asm volatile("mov %%ss,%k0" : "=a"(newregs->ss)); >> >+ asm volatile("mov %%cs,%k0" : "=a"(newregs->cs)); >> > #ifdef CONFIG_X86_32 >> >- asm volatile("movl %%ebx,%0" : "=m"(newregs->bx)); >> >- asm volatile("movl %%ecx,%0" : "=m"(newregs->cx)); >> >- asm volatile("movl %%edx,%0" : "=m"(newregs->dx)); >> >- asm volatile("movl %%esi,%0" : "=m"(newregs->si)); >> >- asm volatile("movl %%edi,%0" : "=m"(newregs->di)); >> >- asm volatile("movl %%ebp,%0" : "=m"(newregs->bp)); >> >- asm volatile("movl %%eax,%0" : "=m"(newregs->ax)); >> >- asm volatile("movl %%esp,%0" : "=m"(newregs->sp)); >> >- asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); >> >- asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); >> >- asm volatile("movl %%ds, %%eax;" :"=a"(newregs->ds)); >> >- asm volatile("movl %%es, %%eax;" :"=a"(newregs->es)); >> >- asm volatile("pushfl; popl %0" :"=m"(newregs->flags)); >> >-#else >> >- asm volatile("movq %%rbx,%0" : "=m"(newregs->bx)); >> >- asm volatile("movq %%rcx,%0" : "=m"(newregs->cx)); >> >- asm volatile("movq %%rdx,%0" : "=m"(newregs->dx)); >> >- asm volatile("movq %%rsi,%0" : "=m"(newregs->si)); >> >- asm volatile("movq %%rdi,%0" : "=m"(newregs->di)); >> >- asm volatile("movq %%rbp,%0" : "=m"(newregs->bp)); >> >- asm volatile("movq %%rax,%0" : "=m"(newregs->ax)); >> >- asm volatile("movq %%rsp,%0" : "=m"(newregs->sp)); >> >- asm volatile("movq %%r8,%0" : "=m"(newregs->r8)); >> >- asm volatile("movq %%r9,%0" : "=m"(newregs->r9)); >> >- asm volatile("movq %%r10,%0" : "=m"(newregs->r10)); >> >- asm volatile("movq %%r11,%0" : "=m"(newregs->r11)); >> >- asm volatile("movq %%r12,%0" : "=m"(newregs->r12)); >> >- asm volatile("movq %%r13,%0" : "=m"(newregs->r13)); >> >- asm volatile("movq %%r14,%0" : "=m"(newregs->r14)); >> >- asm volatile("movq %%r15,%0" : "=m"(newregs->r15)); >> >- asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); >> >- asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); >> >- asm volatile("pushfq; popq %0" :"=m"(newregs->flags)); >> >+ asm volatile("mov %%ds,%k0" : "=a"(newregs->ds)); >> >+ asm volatile("mov %%es,%k0" : "=a"(newregs->es)); >> > #endif >> >+ asm volatile("pushf\n\t" >> >+ "pop %0" : "=m"(newregs->flags)); >> > newregs->ip = _THIS_IP_; >> > } >> > } >> >> Incidentally, doing this in C code is obviously completely broken, especially doing it in multiple statements. You have no idea what the compiler has messed with before you get there. > >These are "asm volatile" statemets, so at least they won't be >scheduled in a different way. OTOH, please note that the patch is very >carefully written to not change code flow, usage of hardregs in the >inline asm is usually the sign of fragile code. > >Uros. > That doesn't matter, though; that only means they can't be moved relatively to each other, but the compiler is perfectly capable of inserting code before, or in between. Your patch might be a functional null, but the code is broken on a deep and fundamental basis. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [tip: x86/core] x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> 2025-03-06 14:52 [PATCH v2] x86/kexec: Merge x86_32 and x86_64 code using macros from asm.h Uros Bizjak 2025-03-06 21:33 ` [tip: x86/asm] x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> tip-bot2 for Uros Bizjak @ 2025-03-19 11:03 ` tip-bot2 for Uros Bizjak 1 sibling, 0 replies; 6+ messages in thread From: tip-bot2 for Uros Bizjak @ 2025-03-19 11:03 UTC (permalink / raw) To: linux-tip-commits Cc: Uros Bizjak, Ingo Molnar, David Woodhouse, Baoquan He, Vivek Goyal, Dave Young, Ard Biesheuvel, H. Peter Anvin, x86, linux-kernel The following commit has been merged into the x86/core branch of tip: Commit-ID: a9deda695972cb53fe815e175b7d66757964764e Gitweb: https://git.kernel.org/tip/a9deda695972cb53fe815e175b7d66757964764e Author: Uros Bizjak <ubizjak@gmail.com> AuthorDate: Thu, 06 Mar 2025 15:52:11 +01:00 Committer: Ingo Molnar <mingo@kernel.org> CommitterDate: Wed, 19 Mar 2025 11:26:24 +01:00 x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> Merge common x86_32 and x86_64 code in crash_setup_regs() using macros from <asm/asm.h>. The compiled object files before and after the patch are unchanged. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lore.kernel.org/r/20250306145227.55819-1-ubizjak@gmail.com --- arch/x86/include/asm/kexec.h | 58 +++++++++++++++-------------------- 1 file changed, 25 insertions(+), 33 deletions(-) diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h index 8ad1874..e3589d6 100644 --- a/arch/x86/include/asm/kexec.h +++ b/arch/x86/include/asm/kexec.h @@ -18,6 +18,7 @@ #include <linux/string.h> #include <linux/kernel.h> +#include <asm/asm.h> #include <asm/page.h> #include <asm/ptrace.h> @@ -71,41 +72,32 @@ static inline void crash_setup_regs(struct pt_regs *newregs, if (oldregs) { memcpy(newregs, oldregs, sizeof(*newregs)); } else { + asm volatile("mov %%" _ASM_BX ",%0" : "=m"(newregs->bx)); + asm volatile("mov %%" _ASM_CX ",%0" : "=m"(newregs->cx)); + asm volatile("mov %%" _ASM_DX ",%0" : "=m"(newregs->dx)); + asm volatile("mov %%" _ASM_SI ",%0" : "=m"(newregs->si)); + asm volatile("mov %%" _ASM_DI ",%0" : "=m"(newregs->di)); + asm volatile("mov %%" _ASM_BP ",%0" : "=m"(newregs->bp)); + asm volatile("mov %%" _ASM_AX ",%0" : "=m"(newregs->ax)); + asm volatile("mov %%" _ASM_SP ",%0" : "=m"(newregs->sp)); +#ifdef CONFIG_X86_64 + asm volatile("mov %%r8,%0" : "=m"(newregs->r8)); + asm volatile("mov %%r9,%0" : "=m"(newregs->r9)); + asm volatile("mov %%r10,%0" : "=m"(newregs->r10)); + asm volatile("mov %%r11,%0" : "=m"(newregs->r11)); + asm volatile("mov %%r12,%0" : "=m"(newregs->r12)); + asm volatile("mov %%r13,%0" : "=m"(newregs->r13)); + asm volatile("mov %%r14,%0" : "=m"(newregs->r14)); + asm volatile("mov %%r15,%0" : "=m"(newregs->r15)); +#endif + asm volatile("mov %%ss,%k0" : "=a"(newregs->ss)); + asm volatile("mov %%cs,%k0" : "=a"(newregs->cs)); #ifdef CONFIG_X86_32 - asm volatile("movl %%ebx,%0" : "=m"(newregs->bx)); - asm volatile("movl %%ecx,%0" : "=m"(newregs->cx)); - asm volatile("movl %%edx,%0" : "=m"(newregs->dx)); - asm volatile("movl %%esi,%0" : "=m"(newregs->si)); - asm volatile("movl %%edi,%0" : "=m"(newregs->di)); - asm volatile("movl %%ebp,%0" : "=m"(newregs->bp)); - asm volatile("movl %%eax,%0" : "=m"(newregs->ax)); - asm volatile("movl %%esp,%0" : "=m"(newregs->sp)); - asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); - asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); - asm volatile("movl %%ds, %%eax;" :"=a"(newregs->ds)); - asm volatile("movl %%es, %%eax;" :"=a"(newregs->es)); - asm volatile("pushfl; popl %0" :"=m"(newregs->flags)); -#else - asm volatile("movq %%rbx,%0" : "=m"(newregs->bx)); - asm volatile("movq %%rcx,%0" : "=m"(newregs->cx)); - asm volatile("movq %%rdx,%0" : "=m"(newregs->dx)); - asm volatile("movq %%rsi,%0" : "=m"(newregs->si)); - asm volatile("movq %%rdi,%0" : "=m"(newregs->di)); - asm volatile("movq %%rbp,%0" : "=m"(newregs->bp)); - asm volatile("movq %%rax,%0" : "=m"(newregs->ax)); - asm volatile("movq %%rsp,%0" : "=m"(newregs->sp)); - asm volatile("movq %%r8,%0" : "=m"(newregs->r8)); - asm volatile("movq %%r9,%0" : "=m"(newregs->r9)); - asm volatile("movq %%r10,%0" : "=m"(newregs->r10)); - asm volatile("movq %%r11,%0" : "=m"(newregs->r11)); - asm volatile("movq %%r12,%0" : "=m"(newregs->r12)); - asm volatile("movq %%r13,%0" : "=m"(newregs->r13)); - asm volatile("movq %%r14,%0" : "=m"(newregs->r14)); - asm volatile("movq %%r15,%0" : "=m"(newregs->r15)); - asm volatile("movl %%ss, %%eax;" :"=a"(newregs->ss)); - asm volatile("movl %%cs, %%eax;" :"=a"(newregs->cs)); - asm volatile("pushfq; popq %0" :"=m"(newregs->flags)); + asm volatile("mov %%ds,%k0" : "=a"(newregs->ds)); + asm volatile("mov %%es,%k0" : "=a"(newregs->es)); #endif + asm volatile("pushf\n\t" + "pop %0" : "=m"(newregs->flags)); newregs->ip = _THIS_IP_; } } ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2025-03-19 11:03 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2025-03-06 14:52 [PATCH v2] x86/kexec: Merge x86_32 and x86_64 code using macros from asm.h Uros Bizjak 2025-03-06 21:33 ` [tip: x86/asm] x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> tip-bot2 for Uros Bizjak 2025-03-07 3:00 ` H. Peter Anvin 2025-03-07 9:20 ` Uros Bizjak 2025-03-07 11:13 ` H. Peter Anvin 2025-03-19 11:03 ` [tip: x86/core] " tip-bot2 for Uros Bizjak
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