x86: Make alternative instruction pointers relative (59e97e4d) · Commits · e / devices / android_kernel_sony_msm8998

arch/x86/include/asm/alternative-asm.h

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -17,8 +17,8 @@

	.macro altinstruction_entry orig alt feature orig_len alt_len		.macro altinstruction_entry orig alt feature orig_len alt_len
	.align 8		.align 8
	.quad \orig		.long \orig - .
	.quad \alt		.long \alt - .
	.word \feature		.word \feature
	.byte \orig_len		.byte \orig_len
	.byte \alt_len		.byte \alt_len

arch/x86/include/asm/alternative.h

+4 −4

Original line number	Original line	Diff line number	Diff line
	@@ -43,8 +43,8 @@
	#endif		#endif

	struct alt_instr {		struct alt_instr {
	u8 instr; / original instruction */		s32 instr_offset; /* original instruction */
	u8 *replacement;		s32 repl_offset; /* offset to replacement instruction */
	u16 cpuid; /* cpuid bit set for replacement */		u16 cpuid; /* cpuid bit set for replacement */
	u8 instrlen; /* length of original instruction */		u8 instrlen; /* length of original instruction */
	u8 replacementlen; /* length of new instruction, <= instrlen */		u8 replacementlen; /* length of new instruction, <= instrlen */
	@@ -84,8 +84,8 @@ static inline int alternatives_text_reserved(void start, void end)
	"661:\n\t" oldinstr "\n662:\n" \		"661:\n\t" oldinstr "\n662:\n" \
	".section .altinstructions,\"a\"\n" \		".section .altinstructions,\"a\"\n" \
	_ASM_ALIGN "\n" \		_ASM_ALIGN "\n" \
	_ASM_PTR "661b\n" /* label */ \		" .long 661b - .\n" /* label */ \
	_ASM_PTR "663f\n" /* new instruction */ \		" .long 663f - .\n" /* new instruction */ \
	" .word " __stringify(feature) "\n" /* feature bit */ \		" .word " __stringify(feature) "\n" /* feature bit */ \
	" .byte 662b-661b\n" /* sourcelen */ \		" .byte 662b-661b\n" /* sourcelen */ \
	" .byte 664f-663f\n" /* replacementlen */ \		" .byte 664f-663f\n" /* replacementlen */ \

arch/x86/include/asm/cpufeature.h

+4 −4

Original line number	Original line	Diff line number	Diff line
	@@ -331,8 +331,8 @@ static __always_inline __pure bool __static_cpu_has(u16 bit)
	"2:\n"		"2:\n"
	".section .altinstructions,\"a\"\n"		".section .altinstructions,\"a\"\n"
	_ASM_ALIGN "\n"		_ASM_ALIGN "\n"
	_ASM_PTR "1b\n"		" .long 1b - .\n"
	_ASM_PTR "0\n" /* no replacement */		" .long 0\n" /* no replacement */
	" .word %P0\n" /* feature bit */		" .word %P0\n" /* feature bit */
	" .byte 2b - 1b\n" /* source len */		" .byte 2b - 1b\n" /* source len */
	" .byte 0\n" /* replacement len */		" .byte 0\n" /* replacement len */
	@@ -349,8 +349,8 @@ static __always_inline __pure bool __static_cpu_has(u16 bit)
	"2:\n"		"2:\n"
	".section .altinstructions,\"a\"\n"		".section .altinstructions,\"a\"\n"
	_ASM_ALIGN "\n"		_ASM_ALIGN "\n"
	_ASM_PTR "1b\n"		" .long 1b - .\n"
	_ASM_PTR "3f\n"		" .long 3f - .\n"
	" .word %P1\n" /* feature bit */		" .word %P1\n" /* feature bit */
	" .byte 2b - 1b\n" /* source len */		" .byte 2b - 1b\n" /* source len */
	" .byte 4f - 3f\n" /* replacement len */		" .byte 4f - 3f\n" /* replacement len */

arch/x86/kernel/alternative.c

+13 −8

Original line number	Original line	Diff line number	Diff line
	@@ -263,6 +263,7 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
	struct alt_instr *end)		struct alt_instr *end)
	{		{
	struct alt_instr *a;		struct alt_instr *a;
			u8 instr, replacement;
	u8 insnbuf[MAX_PATCH_LEN];		u8 insnbuf[MAX_PATCH_LEN];

	DPRINTK("%s: alt table %p -> %p\n", __func__, start, end);		DPRINTK("%s: alt table %p -> %p\n", __func__, start, end);
	@@ -276,25 +277,29 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
	* order.		* order.
	*/		*/
	for (a = start; a < end; a++) {		for (a = start; a < end; a++) {
	u8 *instr = a->instr;		instr = (u8 *)&a->instr_offset + a->instr_offset;
			replacement = (u8 *)&a->repl_offset + a->repl_offset;
	BUG_ON(a->replacementlen > a->instrlen);		BUG_ON(a->replacementlen > a->instrlen);
	BUG_ON(a->instrlen > sizeof(insnbuf));		BUG_ON(a->instrlen > sizeof(insnbuf));
	BUG_ON(a->cpuid >= NCAPINTS*32);		BUG_ON(a->cpuid >= NCAPINTS*32);
	if (!boot_cpu_has(a->cpuid))		if (!boot_cpu_has(a->cpuid))
	continue;		continue;

			memcpy(insnbuf, replacement, a->replacementlen);

			/* 0xe8 is a relative jump; fix the offset. */
			if (*insnbuf == 0xe8 && a->replacementlen == 5)
			(s32 )(insnbuf + 1) += replacement - instr;

			add_nops(insnbuf + a->replacementlen,
			a->instrlen - a->replacementlen);

	#ifdef CONFIG_X86_64		#ifdef CONFIG_X86_64
	/* vsyscall code is not mapped yet. resolve it manually. */		/* vsyscall code is not mapped yet. resolve it manually. */
	if (instr >= (u8 )VSYSCALL_START && instr < (u8)VSYSCALL_END) {		if (instr >= (u8 )VSYSCALL_START && instr < (u8)VSYSCALL_END) {
	instr = __va(instr - (u8)VSYSCALL_START + (u8)__pa_symbol(&__vsyscall_0));		instr = __va(instr - (u8)VSYSCALL_START + (u8)__pa_symbol(&__vsyscall_0));
	DPRINTK("%s: vsyscall fixup: %p => %p\n",
	__func__, a->instr, instr);
	}		}
	#endif		#endif
	memcpy(insnbuf, a->replacement, a->replacementlen);
	if (*insnbuf == 0xe8 && a->replacementlen == 5)
	(s32 )(insnbuf + 1) += a->replacement - a->instr;
	add_nops(insnbuf + a->replacementlen,
	a->instrlen - a->replacementlen);
	text_poke_early(instr, insnbuf, a->instrlen);		text_poke_early(instr, insnbuf, a->instrlen);
	}		}
	}		}

arch/x86/lib/copy_page_64.S

+3 −6

Original line number	Original line	Diff line number	Diff line
	@@ -2,6 +2,7 @@

	#include <linux/linkage.h>		#include <linux/linkage.h>
	#include <asm/dwarf2.h>		#include <asm/dwarf2.h>
			#include <asm/alternative-asm.h>

	ALIGN		ALIGN
	copy_page_c:		copy_page_c:
	@@ -110,10 +111,6 @@ ENDPROC(copy_page)
	2:		2:
	.previous		.previous
	.section .altinstructions,"a"		.section .altinstructions,"a"
	.align 8		altinstruction_entry copy_page, 1b, X86_FEATURE_REP_GOOD, \
	.quad copy_page		.Lcopy_page_end-copy_page, 2b-1b
	.quad 1b
	.word X86_FEATURE_REP_GOOD
	.byte .Lcopy_page_end - copy_page
	.byte 2b - 1b
	.previous		.previous