From 22d3243de86bc92d874abb7c5b185d5c47aba323 Mon Sep 17 00:00:00 2001 From: Jim Bos Date: Mon, 15 Nov 2010 21:22:37 +0100 Subject: Fix gcc 4.5.1 miscompiling drivers/char/i8k.c (again) The fix in commit 6b4e81db2552 ("i8k: Tell gcc that *regs gets clobbered") to work around the gcc miscompiling i8k.c to add "+m (*regs)" caused register pressure problems and a build failure. Changing the 'asm' statement to 'asm volatile' instead should prevent that and works around the gcc bug as well, so we can remove the "+m". [ Background on the gcc bug: a memory clobber fails to mark the function the asm resides in as non-pure (aka "__attribute__((const))"), so if the function does nothing else that triggers the non-pure logic, gcc will think that that function has no side effects at all. As a result, callers will be mis-compiled. Adding the "+m" made gcc see that it's not a pure function, and so does "asm volatile". The problem was never really the need to mark "*regs" as changed, since the memory clobber did that part - the problem was just a bug in the gcc "pure" function analysis - Linus ] Signed-off-by: Jim Bos Acked-by: Jakub Jelinek Cc: Andi Kleen Cc: Andreas Schwab Signed-off-by: Linus Torvalds --- drivers/char/i8k.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/char') diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c index f0863be..d72433f 100644 --- a/drivers/char/i8k.c +++ b/drivers/char/i8k.c @@ -120,7 +120,7 @@ static int i8k_smm(struct smm_regs *regs) int eax = regs->eax; #if defined(CONFIG_X86_64) - asm("pushq %%rax\n\t" + asm volatile("pushq %%rax\n\t" "movl 0(%%rax),%%edx\n\t" "pushq %%rdx\n\t" "movl 4(%%rax),%%ebx\n\t" @@ -142,11 +142,11 @@ static int i8k_smm(struct smm_regs *regs) "lahf\n\t" "shrl $8,%%eax\n\t" "andl $1,%%eax\n" - :"=a"(rc), "+m" (*regs) + :"=a"(rc) : "a"(regs) : "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory"); #else - asm("pushl %%eax\n\t" + asm volatile("pushl %%eax\n\t" "movl 0(%%eax),%%edx\n\t" "push %%edx\n\t" "movl 4(%%eax),%%ebx\n\t" @@ -168,7 +168,7 @@ static int i8k_smm(struct smm_regs *regs) "lahf\n\t" "shrl $8,%%eax\n\t" "andl $1,%%eax\n" - :"=a"(rc), "+m" (*regs) + :"=a"(rc) : "a"(regs) : "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory"); #endif -- cgit v1.1 From 451a3c24b0135bce54542009b5fde43846c7cf67 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 17 Nov 2010 16:26:55 +0100 Subject: BKL: remove extraneous #include The big kernel lock has been removed from all these files at some point, leaving only the #include. Remove this too as a cleanup. Signed-off-by: Arnd Bergmann Signed-off-by: Linus Torvalds --- drivers/char/agp/frontend.c | 1 - drivers/char/amiserial.c | 1 - drivers/char/briq_panel.c | 1 - drivers/char/hpet.c | 1 - drivers/char/hw_random/core.c | 1 - drivers/char/istallion.c | 1 - drivers/char/serial167.c | 1 - drivers/char/specialix.c | 1 - drivers/char/stallion.c | 1 - drivers/char/sx.c | 1 - drivers/char/uv_mmtimer.c | 1 - 11 files changed, 11 deletions(-) (limited to 'drivers/char') diff --git a/drivers/char/agp/frontend.c b/drivers/char/agp/frontend.c index 43412c0..3cb4539 100644 --- a/drivers/char/agp/frontend.c +++ b/drivers/char/agp/frontend.c @@ -39,7 +39,6 @@ #include #include #include -#include #include #include #include "agp.h" diff --git a/drivers/char/amiserial.c b/drivers/char/amiserial.c index c0bd6f4..6ee3348 100644 --- a/drivers/char/amiserial.c +++ b/drivers/char/amiserial.c @@ -81,7 +81,6 @@ static char *serial_version = "4.30"; #include #include #include -#include #include #include #include diff --git a/drivers/char/briq_panel.c b/drivers/char/briq_panel.c index f6718f0..095ab90 100644 --- a/drivers/char/briq_panel.c +++ b/drivers/char/briq_panel.c @@ -6,7 +6,6 @@ #include -#include #include #include #include diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c index 55b8667..7066e80 100644 --- a/drivers/char/hpet.c +++ b/drivers/char/hpet.c @@ -14,7 +14,6 @@ #include #include #include -#include #include #include #include diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 788da05..2016aad 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -37,7 +37,6 @@ #include #include #include -#include #include #include #include diff --git a/drivers/char/istallion.c b/drivers/char/istallion.c index 667abd23..7c6de4c 100644 --- a/drivers/char/istallion.c +++ b/drivers/char/istallion.c @@ -21,7 +21,6 @@ #include #include #include -#include #include #include #include diff --git a/drivers/char/serial167.c b/drivers/char/serial167.c index f646725..748c3b0 100644 --- a/drivers/char/serial167.c +++ b/drivers/char/serial167.c @@ -52,7 +52,6 @@ #include #include #include -#include #include #include #include diff --git a/drivers/char/specialix.c b/drivers/char/specialix.c index 9f8495b..a7616d2 100644 --- a/drivers/char/specialix.c +++ b/drivers/char/specialix.c @@ -87,7 +87,6 @@ #include #include #include -#include #include #include #include diff --git a/drivers/char/stallion.c b/drivers/char/stallion.c index 4bef6ab..461a5a0 100644 --- a/drivers/char/stallion.c +++ b/drivers/char/stallion.c @@ -40,7 +40,6 @@ #include #include #include -#include #include #include #include diff --git a/drivers/char/sx.c b/drivers/char/sx.c index e53f168..a786326 100644 --- a/drivers/char/sx.c +++ b/drivers/char/sx.c @@ -216,7 +216,6 @@ #include #include #include -#include #include #include #include diff --git a/drivers/char/uv_mmtimer.c b/drivers/char/uv_mmtimer.c index 493b47a..956ebe2 100644 --- a/drivers/char/uv_mmtimer.c +++ b/drivers/char/uv_mmtimer.c @@ -23,7 +23,6 @@ #include #include #include -#include #include #include -- cgit v1.1