* [PATCH v5 0/3] RISC-V: three fixup and cleanups
@ 2022-07-01 12:05 Xianting Tian
2022-07-01 12:05 ` [PATCH v5 1/3] RISC-V: use __smp_processor_id() instead of smp_processor_id() Xianting Tian
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Xianting Tian @ 2022-07-01 12:05 UTC (permalink / raw)
To: palmer; +Cc: guoren, linux-kernel, linux-riscv
Hi Palmer,
These 3 patches are some obviously fixup and cleanups, please have a look, thanks.
Xianting Tian (2):
RISC-V: use __smp_processor_id() instead of smp_processor_id()
RISC-V: Fixup fast call of crash_kexec()
Guo Ren (1):
riscv: atomic: Clean up unnecessary acquire and release definitions
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v5 1/3] RISC-V: use __smp_processor_id() instead of smp_processor_id() 2022-07-01 12:05 [PATCH v5 0/3] RISC-V: three fixup and cleanups Xianting Tian @ 2022-07-01 12:05 ` Xianting Tian 2022-07-01 12:05 ` [PATCH v5 2/3] RISC-V: Fixup fast call of crash_kexec() Xianting Tian 2022-07-01 12:05 ` [PATCH v5 3/3] riscv: atomic: Clean up unnecessary acquire and release definitions Xianting Tian 2 siblings, 0 replies; 4+ messages in thread From: Xianting Tian @ 2022-07-01 12:05 UTC (permalink / raw) To: palmer; +Cc: guoren, linux-kernel, linux-riscv, Xianting Tian Use __smp_processor_id() to avoid check the preemption context when CONFIG_DEBUG_PREEMPT enabled, as we will enter crash kernel and no return. Without the patch, [ 103.781044] sysrq: Trigger a crash [ 103.784625] Kernel panic - not syncing: sysrq triggered crash [ 103.837634] CPU1: off [ 103.889668] CPU2: off [ 103.933479] CPU3: off [ 103.939424] Starting crashdump kernel... [ 103.943442] BUG: using smp_processor_id() in preemptible [00000000] code: sh/346 [ 103.950884] caller is debug_smp_processor_id+0x1c/0x26 [ 103.956051] CPU: 0 PID: 346 Comm: sh Kdump: loaded Not tainted 5.10.113-00002-gce03f03bf4ec-dirty #149 [ 103.965355] Call Trace: [ 103.967805] [<ffffffe00020372a>] walk_stackframe+0x0/0xa2 [ 103.973206] [<ffffffe000bcf1f4>] show_stack+0x32/0x3e [ 103.978258] [<ffffffe000bd382a>] dump_stack_lvl+0x72/0x8e [ 103.983655] [<ffffffe000bd385a>] dump_stack+0x14/0x1c [ 103.988705] [<ffffffe000bdc8fe>] check_preemption_disabled+0x9e/0xaa [ 103.995057] [<ffffffe000bdc926>] debug_smp_processor_id+0x1c/0x26 [ 104.001150] [<ffffffe000206c64>] machine_kexec+0x22/0xd0 [ 104.006463] [<ffffffe000291a7e>] __crash_kexec+0x6a/0xa4 [ 104.011774] [<ffffffe000bcf3fa>] panic+0xfc/0x2b0 [ 104.016480] [<ffffffe000656ca4>] sysrq_reset_seq_param_set+0x0/0x70 [ 104.022745] [<ffffffe000657310>] __handle_sysrq+0x8c/0x154 [ 104.028229] [<ffffffe0006577e8>] write_sysrq_trigger+0x5a/0x6a [ 104.034061] [<ffffffe0003d90e0>] proc_reg_write+0x58/0xd4 [ 104.039459] [<ffffffe00036cff4>] vfs_write+0x7e/0x254 [ 104.044509] [<ffffffe00036d2f6>] ksys_write+0x58/0xbe [ 104.049558] [<ffffffe00036d36a>] sys_write+0xe/0x16 [ 104.054434] [<ffffffe000201b9a>] ret_from_syscall+0x0/0x2 [ 104.067863] Will call new kernel at ecc00000 from hart id 0 [ 104.074939] FDT image at fc5ee000 [ 104.079523] Bye... With the patch we can got clear output, [ 67.740553] sysrq: Trigger a crash [ 67.744166] Kernel panic - not syncing: sysrq triggered crash [ 67.809123] CPU1: off [ 67.865210] CPU2: off [ 67.909075] CPU3: off [ 67.919123] Starting crashdump kernel... [ 67.924900] Will call new kernel at ecc00000 from hart id 0 [ 67.932045] FDT image at fc5ee000 [ 67.935560] Bye... Fixes: 0e105f1d0037 ("riscv: use hart id instead of cpu id on machine_kexec") Reviewed-by: Guo Ren <guoren@kernel.org> Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com> --- Changes from v1: - Add Reviewed-by --- arch/riscv/kernel/machine_kexec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/kernel/machine_kexec.c b/arch/riscv/kernel/machine_kexec.c index df8e24559035..86d1b5f9dfb5 100644 --- a/arch/riscv/kernel/machine_kexec.c +++ b/arch/riscv/kernel/machine_kexec.c @@ -171,7 +171,7 @@ machine_kexec(struct kimage *image) struct kimage_arch *internal = &image->arch; unsigned long jump_addr = (unsigned long) image->start; unsigned long first_ind_entry = (unsigned long) &image->head; - unsigned long this_cpu_id = smp_processor_id(); + unsigned long this_cpu_id = __smp_processor_id(); unsigned long this_hart_id = cpuid_to_hartid_map(this_cpu_id); unsigned long fdt_addr = internal->fdt_addr; void *control_code_buffer = page_address(image->control_code_page); -- 2.17.1 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v5 2/3] RISC-V: Fixup fast call of crash_kexec() 2022-07-01 12:05 [PATCH v5 0/3] RISC-V: three fixup and cleanups Xianting Tian 2022-07-01 12:05 ` [PATCH v5 1/3] RISC-V: use __smp_processor_id() instead of smp_processor_id() Xianting Tian @ 2022-07-01 12:05 ` Xianting Tian 2022-07-01 12:05 ` [PATCH v5 3/3] riscv: atomic: Clean up unnecessary acquire and release definitions Xianting Tian 2 siblings, 0 replies; 4+ messages in thread From: Xianting Tian @ 2022-07-01 12:05 UTC (permalink / raw) To: palmer; +Cc: guoren, linux-kernel, linux-riscv, Xianting Tian Currently, almost all archs (x86, arm64, mips...) support fast call of crash_kexec() when "regs && kexec_should_crash()" is true. But RISC-V not, it can only enter crash system via panic(). However panic() doesn't pass the regs of the real accident scene to crash_kexec(), it caused we can't get accurate backtrace via gdb, $ riscv64-linux-gnu-gdb vmlinux vmcore Reading symbols from vmlinux... [New LWP 95] #0 console_unlock () at kernel/printk/printk.c:2557 2557 if (do_cond_resched) (gdb) bt #0 console_unlock () at kernel/printk/printk.c:2557 #1 0x0000000000000000 in ?? () With the patch we can get the accurate backtrace, $ riscv64-linux-gnu-gdb vmlinux vmcore Reading symbols from vmlinux... [New LWP 95] #0 0xffffffe00063a4e0 in test_thread (data=<optimized out>) at drivers/test_crash.c:81 81 *(int *)p = 0xdead; (gdb) (gdb) bt #0 0xffffffe00064d5c0 in test_thread (data=<optimized out>) at drivers/test_crash.c:81 #1 0x0000000000000000 in ?? () Test code to produce NULL address dereference in test_crash.c, void *p = NULL; *(int *)p = 0xdead; Fixes: 76d2a0493a17 ("RISC-V: Init and Halt Code") Reviewed-by: Guo Ren <guoren@kernel.org> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com> --- arch/riscv/kernel/traps.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index b40426509244..39d0f8bba4b4 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -16,6 +16,7 @@ #include <linux/mm.h> #include <linux/module.h> #include <linux/irq.h> +#include <linux/kexec.h> #include <asm/asm-prototypes.h> #include <asm/bug.h> @@ -44,6 +45,9 @@ void die(struct pt_regs *regs, const char *str) ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV); + if (regs && kexec_should_crash(current)) + crash_kexec(regs); + bust_spinlocks(0); add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); spin_unlock_irq(&die_lock); -- 2.17.1 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v5 3/3] riscv: atomic: Clean up unnecessary acquire and release definitions 2022-07-01 12:05 [PATCH v5 0/3] RISC-V: three fixup and cleanups Xianting Tian 2022-07-01 12:05 ` [PATCH v5 1/3] RISC-V: use __smp_processor_id() instead of smp_processor_id() Xianting Tian 2022-07-01 12:05 ` [PATCH v5 2/3] RISC-V: Fixup fast call of crash_kexec() Xianting Tian @ 2022-07-01 12:05 ` Xianting Tian 2 siblings, 0 replies; 4+ messages in thread From: Xianting Tian @ 2022-07-01 12:05 UTC (permalink / raw) To: palmer; +Cc: guoren, linux-kernel, linux-riscv, Guo Ren, Arnd Bergmann From: Guo Ren <guoren@linux.alibaba.com> Clean up unnecessary xchg_acquire, xchg_release, and cmpxchg_release custom definitions, because the generic implementation is the same as the riscv custom implementation. Before the patch: 000000000000024e <.LBB238>: ops = xchg_acquire(pending_ipis, 0); 24e: 089937af amoswap.d a5,s1,(s2) 252: 0230000f fence r,rw 0000000000000256 <.LBB243>: ops = xchg_release(pending_ipis, 0); 256: 0310000f fence rw,w 25a: 089934af amoswap.d s1,s1,(s2) After the patch: 000000000000026e <.LBB245>: ops = xchg_acquire(pending_ipis, 0); 26e: 089937af amoswap.d a5,s1,(s2) 0000000000000272 <.LBE247>: 272: 0230000f fence r,rw 0000000000000276 <.LBB249>: ops = xchg_release(pending_ipis, 0); 276: 0310000f fence rw,w 000000000000027a <.LBB251>: 27a: 089934af amoswap.d s1,s1,(s2) Only cmpxchg_acquire is necessary (It prevents unnecessary acquire ordering when the value from lr is different from old). Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Palmer Dabbelt <palmer@dabbelt.com> --- arch/riscv/include/asm/atomic.h | 19 ----- arch/riscv/include/asm/cmpxchg.h | 116 ------------------------------- 2 files changed, 135 deletions(-) diff --git a/arch/riscv/include/asm/atomic.h b/arch/riscv/include/asm/atomic.h index 0dfe9d857a76..83636320ba95 100644 --- a/arch/riscv/include/asm/atomic.h +++ b/arch/riscv/include/asm/atomic.h @@ -249,16 +249,6 @@ c_t arch_atomic##prefix##_xchg_relaxed(atomic##prefix##_t *v, c_t n) \ return __xchg_relaxed(&(v->counter), n, size); \ } \ static __always_inline \ -c_t arch_atomic##prefix##_xchg_acquire(atomic##prefix##_t *v, c_t n) \ -{ \ - return __xchg_acquire(&(v->counter), n, size); \ -} \ -static __always_inline \ -c_t arch_atomic##prefix##_xchg_release(atomic##prefix##_t *v, c_t n) \ -{ \ - return __xchg_release(&(v->counter), n, size); \ -} \ -static __always_inline \ c_t arch_atomic##prefix##_xchg(atomic##prefix##_t *v, c_t n) \ { \ return __xchg(&(v->counter), n, size); \ @@ -276,12 +266,6 @@ c_t arch_atomic##prefix##_cmpxchg_acquire(atomic##prefix##_t *v, \ return __cmpxchg_acquire(&(v->counter), o, n, size); \ } \ static __always_inline \ -c_t arch_atomic##prefix##_cmpxchg_release(atomic##prefix##_t *v, \ - c_t o, c_t n) \ -{ \ - return __cmpxchg_release(&(v->counter), o, n, size); \ -} \ -static __always_inline \ c_t arch_atomic##prefix##_cmpxchg(atomic##prefix##_t *v, c_t o, c_t n) \ { \ return __cmpxchg(&(v->counter), o, n, size); \ @@ -299,12 +283,9 @@ c_t arch_atomic##prefix##_cmpxchg(atomic##prefix##_t *v, c_t o, c_t n) \ ATOMIC_OPS() #define arch_atomic_xchg_relaxed arch_atomic_xchg_relaxed -#define arch_atomic_xchg_acquire arch_atomic_xchg_acquire -#define arch_atomic_xchg_release arch_atomic_xchg_release #define arch_atomic_xchg arch_atomic_xchg #define arch_atomic_cmpxchg_relaxed arch_atomic_cmpxchg_relaxed #define arch_atomic_cmpxchg_acquire arch_atomic_cmpxchg_acquire -#define arch_atomic_cmpxchg_release arch_atomic_cmpxchg_release #define arch_atomic_cmpxchg arch_atomic_cmpxchg #undef ATOMIC_OPS diff --git a/arch/riscv/include/asm/cmpxchg.h b/arch/riscv/include/asm/cmpxchg.h index 12debce235e5..67ab6375b650 100644 --- a/arch/riscv/include/asm/cmpxchg.h +++ b/arch/riscv/include/asm/cmpxchg.h @@ -44,76 +44,6 @@ _x_, sizeof(*(ptr))); \ }) -#define __xchg_acquire(ptr, new, size) \ -({ \ - __typeof__(ptr) __ptr = (ptr); \ - __typeof__(new) __new = (new); \ - __typeof__(*(ptr)) __ret; \ - switch (size) { \ - case 4: \ - __asm__ __volatile__ ( \ - " amoswap.w %0, %2, %1\n" \ - RISCV_ACQUIRE_BARRIER \ - : "=r" (__ret), "+A" (*__ptr) \ - : "r" (__new) \ - : "memory"); \ - break; \ - case 8: \ - __asm__ __volatile__ ( \ - " amoswap.d %0, %2, %1\n" \ - RISCV_ACQUIRE_BARRIER \ - : "=r" (__ret), "+A" (*__ptr) \ - : "r" (__new) \ - : "memory"); \ - break; \ - default: \ - BUILD_BUG(); \ - } \ - __ret; \ -}) - -#define arch_xchg_acquire(ptr, x) \ -({ \ - __typeof__(*(ptr)) _x_ = (x); \ - (__typeof__(*(ptr))) __xchg_acquire((ptr), \ - _x_, sizeof(*(ptr))); \ -}) - -#define __xchg_release(ptr, new, size) \ -({ \ - __typeof__(ptr) __ptr = (ptr); \ - __typeof__(new) __new = (new); \ - __typeof__(*(ptr)) __ret; \ - switch (size) { \ - case 4: \ - __asm__ __volatile__ ( \ - RISCV_RELEASE_BARRIER \ - " amoswap.w %0, %2, %1\n" \ - : "=r" (__ret), "+A" (*__ptr) \ - : "r" (__new) \ - : "memory"); \ - break; \ - case 8: \ - __asm__ __volatile__ ( \ - RISCV_RELEASE_BARRIER \ - " amoswap.d %0, %2, %1\n" \ - : "=r" (__ret), "+A" (*__ptr) \ - : "r" (__new) \ - : "memory"); \ - break; \ - default: \ - BUILD_BUG(); \ - } \ - __ret; \ -}) - -#define arch_xchg_release(ptr, x) \ -({ \ - __typeof__(*(ptr)) _x_ = (x); \ - (__typeof__(*(ptr))) __xchg_release((ptr), \ - _x_, sizeof(*(ptr))); \ -}) - #define __xchg(ptr, new, size) \ ({ \ __typeof__(ptr) __ptr = (ptr); \ @@ -253,52 +183,6 @@ _o_, _n_, sizeof(*(ptr))); \ }) -#define __cmpxchg_release(ptr, old, new, size) \ -({ \ - __typeof__(ptr) __ptr = (ptr); \ - __typeof__(*(ptr)) __old = (old); \ - __typeof__(*(ptr)) __new = (new); \ - __typeof__(*(ptr)) __ret; \ - register unsigned int __rc; \ - switch (size) { \ - case 4: \ - __asm__ __volatile__ ( \ - RISCV_RELEASE_BARRIER \ - "0: lr.w %0, %2\n" \ - " bne %0, %z3, 1f\n" \ - " sc.w %1, %z4, %2\n" \ - " bnez %1, 0b\n" \ - "1:\n" \ - : "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \ - : "rJ" ((long)__old), "rJ" (__new) \ - : "memory"); \ - break; \ - case 8: \ - __asm__ __volatile__ ( \ - RISCV_RELEASE_BARRIER \ - "0: lr.d %0, %2\n" \ - " bne %0, %z3, 1f\n" \ - " sc.d %1, %z4, %2\n" \ - " bnez %1, 0b\n" \ - "1:\n" \ - : "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \ - : "rJ" (__old), "rJ" (__new) \ - : "memory"); \ - break; \ - default: \ - BUILD_BUG(); \ - } \ - __ret; \ -}) - -#define arch_cmpxchg_release(ptr, o, n) \ -({ \ - __typeof__(*(ptr)) _o_ = (o); \ - __typeof__(*(ptr)) _n_ = (n); \ - (__typeof__(*(ptr))) __cmpxchg_release((ptr), \ - _o_, _n_, sizeof(*(ptr))); \ -}) - #define __cmpxchg(ptr, old, new, size) \ ({ \ __typeof__(ptr) __ptr = (ptr); \ -- 2.17.1 ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-07-01 12:06 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-07-01 12:05 [PATCH v5 0/3] RISC-V: three fixup and cleanups Xianting Tian 2022-07-01 12:05 ` [PATCH v5 1/3] RISC-V: use __smp_processor_id() instead of smp_processor_id() Xianting Tian 2022-07-01 12:05 ` [PATCH v5 2/3] RISC-V: Fixup fast call of crash_kexec() Xianting Tian 2022-07-01 12:05 ` [PATCH v5 3/3] riscv: atomic: Clean up unnecessary acquire and release definitions Xianting Tian
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