From edc953fa4ebc0265ef3b1754fe116a9fd4264e15 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Tue, 28 Apr 2009 11:13:46 -0400 Subject: x86: clean up alternative.h Alternative header duplicates assembly that could be merged in one single macro. Merging this into this macro also allows to directly declare ALTERNATIVE() statements within assembly code. Uses a __stringify() of the feature bits rather than passing a "i" operand. Leave the old %0 operand as-is (set to 0), unused to stay compatible with API. (v2: tab alignment fixes) [ Impact: cleanup ] Signed-off-by: Mathieu Desnoyers LKML-Reference: <20090428151346.GA31212@Krystal> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/alternative.h | 59 +++++++++++++++----------------------- 1 file changed, 23 insertions(+), 36 deletions(-) diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index f6aa18e..1a37bcd 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -3,6 +3,7 @@ #include #include +#include #include /* @@ -74,6 +75,22 @@ static inline void alternatives_smp_switch(int smp) {} const unsigned char *const *find_nop_table(void); +/* alternative assembly primitive: */ +#define ALTERNATIVE(oldinstr, newinstr, feature) \ + \ + "661:\n\t" oldinstr "\n662:\n" \ + ".section .altinstructions,\"a\"\n" \ + _ASM_ALIGN "\n" \ + _ASM_PTR "661b\n" /* label */ \ + _ASM_PTR "663f\n" /* new instruction */ \ + " .byte " __stringify(feature) "\n" /* feature bit */ \ + " .byte 662b-661b\n" /* sourcelen */ \ + " .byte 664f-663f\n" /* replacementlen */ \ + ".previous\n" \ + ".section .altinstr_replacement, \"ax\"\n" \ + "663:\n\t" newinstr "\n664:\n" /* replacement */ \ + ".previous" + /* * Alternative instructions for different CPU types or capabilities. * @@ -87,18 +104,7 @@ const unsigned char *const *find_nop_table(void); * without volatile and memory clobber. */ #define alternative(oldinstr, newinstr, feature) \ - asm volatile ("661:\n\t" oldinstr "\n662:\n" \ - ".section .altinstructions,\"a\"\n" \ - _ASM_ALIGN "\n" \ - _ASM_PTR "661b\n" /* label */ \ - _ASM_PTR "663f\n" /* new instruction */ \ - " .byte %c0\n" /* feature bit */ \ - " .byte 662b-661b\n" /* sourcelen */ \ - " .byte 664f-663f\n" /* replacementlen */ \ - ".previous\n" \ - ".section .altinstr_replacement,\"ax\"\n" \ - "663:\n\t" newinstr "\n664:\n" /* replacement */ \ - ".previous" :: "i" (feature) : "memory") + asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory") /* * Alternative inline assembly with input. @@ -109,35 +115,16 @@ const unsigned char *const *find_nop_table(void); * Best is to use constraints that are fixed size (like (%1) ... "r") * If you use variable sized constraints like "m" or "g" in the * replacement make sure to pad to the worst case length. + * Leaving an unused argument 0 to keep API compatibility. */ #define alternative_input(oldinstr, newinstr, feature, input...) \ - asm volatile ("661:\n\t" oldinstr "\n662:\n" \ - ".section .altinstructions,\"a\"\n" \ - _ASM_ALIGN "\n" \ - _ASM_PTR "661b\n" /* label */ \ - _ASM_PTR "663f\n" /* new instruction */ \ - " .byte %c0\n" /* feature bit */ \ - " .byte 662b-661b\n" /* sourcelen */ \ - " .byte 664f-663f\n" /* replacementlen */ \ - ".previous\n" \ - ".section .altinstr_replacement,\"ax\"\n" \ - "663:\n\t" newinstr "\n664:\n" /* replacement */ \ - ".previous" :: "i" (feature), ##input) + asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ + : : "i" (0), ## input) /* Like alternative_input, but with a single output argument */ #define alternative_io(oldinstr, newinstr, feature, output, input...) \ - asm volatile ("661:\n\t" oldinstr "\n662:\n" \ - ".section .altinstructions,\"a\"\n" \ - _ASM_ALIGN "\n" \ - _ASM_PTR "661b\n" /* label */ \ - _ASM_PTR "663f\n" /* new instruction */ \ - " .byte %c[feat]\n" /* feature bit */ \ - " .byte 662b-661b\n" /* sourcelen */ \ - " .byte 664f-663f\n" /* replacementlen */ \ - ".previous\n" \ - ".section .altinstr_replacement,\"ax\"\n" \ - "663:\n\t" newinstr "\n664:\n" /* replacement */ \ - ".previous" : output : [feat] "i" (feature), ##input) + asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ + : output : "i" (0), ## input) /* * use this macro(s) if you need more than one output parameter -- cgit v1.1 From d756f4adb9d8a86e347a2d5435bb5cc95744733e Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Mon, 4 May 2009 03:29:52 +0400 Subject: x86, 32-bit: ifdef out struct thread_struct::fs After commit 464d1a78fbf8cf6c7fd970e7b3e2db50a320ce28 aka "[PATCH] i386: Convert i386 PDA code to use %fs" %fs saved during context switch moved from thread_struct to pt_regs and value on thread_struct became unused. [ Impact: reduce thread_struct size on 32-bit ] Signed-off-by: Alexey Dobriyan Cc: containers@lists.linux-foundation.org LKML-Reference: <20090503232952.GI16631@x200.localdomain> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/processor.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index c2cceae..a6732ff 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -428,7 +428,9 @@ struct thread_struct { unsigned short gsindex; #endif unsigned long ip; +#ifdef CONFIG_X86_64 unsigned long fs; +#endif unsigned long gs; /* Hardware debugging registers: */ unsigned long debugreg0; @@ -874,7 +876,6 @@ static inline void spin_lock_prefetch(const void *x) .vm86_info = NULL, \ .sysenter_cs = __KERNEL_CS, \ .io_bitmap_ptr = NULL, \ - .fs = __KERNEL_PERCPU, \ } /* -- cgit v1.1 From 0c23590f00f85467b318ad0c20c36796a5bd4c60 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Mon, 4 May 2009 03:30:15 +0400 Subject: x86, 64-bit: ifdef out struct thread_struct::ip struct thread_struct::ip isn't used on x86_64, struct pt_regs::ip is used instead. kgdb should be reading 0 always, but I can't check it. [ Impact: (potentially) reduce thread_struct size on 64-bit ] Signed-off-by: Alexey Dobriyan Cc: containers@lists.linux-foundation.org LKML-Reference: <20090503233015.GJ16631@x200.localdomain> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/processor.h | 2 ++ arch/x86/kernel/kgdb.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index a6732ff..a9ba743 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -427,7 +427,9 @@ struct thread_struct { unsigned short fsindex; unsigned short gsindex; #endif +#ifdef CONFIG_X86_32 unsigned long ip; +#endif #ifdef CONFIG_X86_64 unsigned long fs; #endif diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index eedfaeb..d07706f 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -141,7 +141,7 @@ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) gdb_regs32[GDB_PS] = *(unsigned long *)(p->thread.sp + 8); gdb_regs32[GDB_CS] = __KERNEL_CS; gdb_regs32[GDB_SS] = __KERNEL_DS; - gdb_regs[GDB_PC] = p->thread.ip; + gdb_regs[GDB_PC] = 0; gdb_regs[GDB_R8] = 0; gdb_regs[GDB_R9] = 0; gdb_regs[GDB_R10] = 0; -- cgit v1.1