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From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
	jpoimboe@redhat.com, mark.rutland@arm.com, dvyukov@google.com,
	seanjc@google.com, pbonzini@redhat.com, mbenes@suse.cz
Subject: [PATCH 17/22] x86,kvm: Remove .fixup usage
Date: Fri, 05 Nov 2021 18:10:40 +0100	[thread overview]
Message-ID: <20211105171821.470393311@infradead.org> (raw)
In-Reply-To: <20211105171023.989862879@infradead.org>

KVM instruction emulation has a gnarly hack where the .fixup does a
return, however there's already a ret right after the 10b label, so
mark that as 11 and have the exception clear %esi to remove the
.fixup.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/kvm/emulate.c |   16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -315,7 +315,7 @@ static int fastop(struct x86_emulate_ctx
 	__FOP_FUNC(#name)
 
 #define __FOP_RET(name) \
-	"ret \n\t" \
+	"11: ret \n\t" \
 	".size " name ", .-" name "\n\t"
 
 #define FOP_RET(name) \
@@ -344,7 +344,7 @@ static int fastop(struct x86_emulate_ctx
 	__FOP_RET(#op "_" #dst)
 
 #define FOP1EEX(op,  dst) \
-	FOP1E(op, dst) _ASM_EXTABLE(10b, kvm_fastop_exception)
+	FOP1E(op, dst) _ASM_EXTABLE_TYPE_REG(10b, 11b, EX_TYPE_ZERO_REG, %esi)
 
 #define FASTOP1(op) \
 	FOP_START(op) \
@@ -434,10 +434,6 @@ static int fastop(struct x86_emulate_ctx
 	#op " %al \n\t" \
 	__FOP_RET(#op)
 
-asm(".pushsection .fixup, \"ax\"\n"
-    "kvm_fastop_exception: xor %esi, %esi; ret\n"
-    ".popsection");
-
 FOP_START(setcc)
 FOP_SETCC(seto)
 FOP_SETCC(setno)
@@ -473,12 +469,8 @@ FOP_END;
  \
 	asm volatile("1:" insn "\n" \
 	             "2:\n" \
-	             ".pushsection .fixup, \"ax\"\n" \
-	             "3: movl $1, %[_fault]\n" \
-	             "   jmp  2b\n" \
-	             ".popsection\n" \
-	             _ASM_EXTABLE(1b, 3b) \
-	             : [_fault] "+qm"(_fault) inoutclob ); \
+		     _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_ONE_REG, %[_fault]) \
+	             : [_fault] "+r"(_fault) inoutclob ); \
  \
 	_fault ? X86EMUL_UNHANDLEABLE : X86EMUL_CONTINUE; \
 })



  parent reply	other threads:[~2021-11-05 17:24 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-05 17:10 [PATCH 00/22] x86: Remove anonymous out-of-line fixups Peter Zijlstra
2021-11-05 17:10 ` [PATCH 01/22] bitfield.h: Fix "type of reg too small for mask" test Peter Zijlstra
2021-11-05 17:10 ` [PATCH 02/22] x86,mmx_32: Remove .fixup usage Peter Zijlstra
2021-11-05 17:10 ` [PATCH 03/22] x86,copy_user_64: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 04/22] x86,copy_mc_64: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 05/22] x86,entry_64: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 06/22] x86,entry_32: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 07/22] x86,extable: Extend extable functionality Peter Zijlstra
2021-11-05 17:10 ` [PATCH 08/22] x86,msr: Remove .fixup usage Peter Zijlstra
2021-11-05 17:10 ` [PATCH 09/22] x86,futex: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 10/22] x86,uaccess: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 11/22] x86,xen: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 12/22] x86,fpu: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 13/22] x86,segment: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 14/22] x86,vmx: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 15/22] x86,checksum_32: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 16/22] x86,sgx: " Peter Zijlstra
2021-11-05 17:10 ` Peter Zijlstra [this message]
2021-11-05 17:10 ` [PATCH 18/22] x86,usercopy_32: Simplify __copy_user_intel_nocache() Peter Zijlstra
2021-11-05 17:10 ` [PATCH 19/22] x86,usercopy: Remove .fixup usage Peter Zijlstra
2021-11-05 17:10 ` [PATCH 20/22] x86,word-at-a-time: " Peter Zijlstra
2021-11-05 18:01   ` Josh Poimboeuf
2021-11-05 18:07     ` Peter Zijlstra
2021-11-08 16:47   ` Josh Poimboeuf
2021-11-08 18:29     ` Peter Zijlstra
2021-11-08 18:53       ` Nick Desaulniers
2021-11-09  8:23         ` Peter Zijlstra
2021-11-09 19:22           ` Nick Desaulniers
2021-11-09 20:59             ` Bill Wendling
2021-11-09 21:21               ` Peter Zijlstra
2021-11-09 21:25                 ` Nick Desaulniers
2021-11-09 22:11                   ` Peter Zijlstra
2021-11-09 22:15                     ` Nick Desaulniers
2021-11-09 21:07             ` Peter Zijlstra
2021-11-10 10:18               ` Peter Zijlstra
2021-11-10 10:46               ` David Laight
2021-11-10 11:09                 ` Peter Zijlstra
2021-11-10 12:20                   ` David Laight
2021-11-12  1:50                     ` Josh Poimboeuf
2021-11-12  9:33                       ` Peter Zijlstra
2021-11-13  5:35                         ` Josh Poimboeuf
2021-11-15 12:36                           ` Miroslav Benes
2021-11-15 13:01                             ` Joe Lawrence
2021-11-15 23:40                               ` Josh Poimboeuf
2021-11-16  7:25                                 ` Miroslav Benes
2021-11-15 12:59                           ` Miroslav Benes
2021-11-16 21:27                             ` Josh Poimboeuf
2021-11-18  7:15                               ` Miroslav Benes
2021-11-22 17:46                       ` Petr Mladek
2021-11-24 17:42                         ` Josh Poimboeuf
2021-11-25  8:18                           ` Petr Mladek
2021-11-10 12:14               ` Segher Boessenkool
2021-11-05 17:10 ` [PATCH 21/22] x86: Remove .fixup section Peter Zijlstra
2021-11-05 17:10 ` [PATCH 22/22] objtool: Remove .fixup handling Peter Zijlstra

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