From d4f1b10365d4f03dd802433e0014cf503e6e930c Mon Sep 17 00:00:00 2001 From: Jike Song Date: Fri, 17 Oct 2008 13:25:07 +0800 Subject: x86: clean up comments wrt. rd{msr|tsc|pmc} The rdmsr instruction(et al) for i386 and x86-64 are semantically same. The only difference is how gcc interpret constraint "A" for these targets. Signed-off-by: Jike Song Signed-off-by: Ingo Molnar --- arch/x86/include/asm/msr.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/x86/include/asm/msr.h') diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index 46be2fa..478a924 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -22,10 +22,10 @@ static inline unsigned long long native_read_tscp(unsigned int *aux) } /* - * i386 calling convention returns 64-bit value in edx:eax, while - * x86_64 returns at rax. Also, the "A" constraint does not really - * mean rdx:rax in x86_64, so we need specialized behaviour for each - * architecture + * both i386 and x86_64 returns 64-bit value in edx:eax, but gcc's "A" + * constraint has different meanings. For i386, "A" means exactly + * edx:eax, while for x86_64 it doesn't mean rdx:rax or edx:eax. Instead, + * it means rax *or* rdx. */ #ifdef CONFIG_X86_64 #define DECLARE_ARGS(val, low, high) unsigned low, high -- cgit v1.1 From 205516c12dbba003c26b42cfb41e598631300106 Mon Sep 17 00:00:00 2001 From: Ken Chen Date: Tue, 16 Dec 2008 00:32:21 -0800 Subject: x86: convert rdtscll() to use __native_read_tsc Impact: micro-optimization Is there any reason why x86 rdtscll have to use the out of line function instead of inline __native_read_tsc()? native_read_tsc and __native_read_tsc is essentially the same functions. Patch to let x86 rdtscll() to use the inline version of read_tsc. Signed-off-by: Ken Chen Signed-off-by: Ingo Molnar --- arch/x86/include/asm/msr.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/include/asm/msr.h') diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index c2a812e..42f639b 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -181,10 +181,10 @@ static inline int rdmsrl_amd_safe(unsigned msr, unsigned long long *p) } #define rdtscl(low) \ - ((low) = (u32)native_read_tsc()) + ((low) = (u32)__native_read_tsc()) #define rdtscll(val) \ - ((val) = native_read_tsc()) + ((val) = __native_read_tsc()) #define rdpmc(counter, low, high) \ do { \ -- cgit v1.1 From 0ca59dd948a51c95d5a366d35f897bc5ef9df55d Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 24 Dec 2008 23:30:02 +0100 Subject: tracing/ftrace: don't trace on early stage of a secondary cpu boot, v3 Impact: fix a crash/hard-reboot on certain configs while enabling cpu runtime On some archs, the boot of a secondary cpu can have an early fragile state. On x86-64, the pda is not initialized on the first stage of a cpu boot but it is needed to get the cpu number and the current task pointer. This data is needed during tracing. As they were dereferenced at this stage, we got a crash while tracing a cpu being enabled at runtime. Some other archs like ia64 can have such kind of issue too. Changes on v2: We dropped the previous solution of a per-arch called function to guess the current state of a cpu. That could slow down the tracing. This patch removes the -pg flag on arch/x86/kernel/cpu/common.c where the low level cpu boot functions exist, on start_secondary() and a helper function used at this stage. Signed-off-by: Frederic Weisbecker Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar --- arch/x86/include/asm/msr.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/x86/include/asm/msr.h') diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index c2a812e..b8a1799 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -85,7 +85,8 @@ static inline void native_write_msr(unsigned int msr, asm volatile("wrmsr" : : "c" (msr), "a"(low), "d" (high) : "memory"); } -static inline int native_write_msr_safe(unsigned int msr, +/* Can be uninlined because referenced by paravirt */ +notrace static inline int native_write_msr_safe(unsigned int msr, unsigned low, unsigned high) { int err; -- cgit v1.1