The new assembly code works on both 32bit and 64bit cpus
and allows for more compiler optimisations by not
requiring smm_regs to be packed. Also since the
SMM handler seems to modify the carry flag, the new
code informs the compiler that the flags register
needs to be saved/restored.
Tested with 32 bit and 64 bit kernels on a Dell Inspiron 3505.
Signed-off-by: Armin Wolf <W_Armin@xxxxxx>
---
drivers/hwmon/dell-smm-hwmon.c | 71 ++++++++--------------------------
1 file changed, 17 insertions(+), 54 deletions(-)
diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index b7016971bb2e..04a41d59da60 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -123,7 +123,7 @@ struct smm_regs {
unsigned int edx;
unsigned int esi;
unsigned int edi;
-} __packed;
+};
static const char * const temp_labels[] = {
"CPU",
@@ -175,59 +175,22 @@ static int i8k_smm_func(void *par)
if (smp_processor_id() != 0)
return -EBUSY;
-#if defined(CONFIG_X86_64)
- asm volatile("pushq %%rax\n\t"
- "movl 0(%%rax),%%edx\n\t"
- "pushq %%rdx\n\t"
- "movl 4(%%rax),%%ebx\n\t"
- "movl 8(%%rax),%%ecx\n\t"
- "movl 12(%%rax),%%edx\n\t"
- "movl 16(%%rax),%%esi\n\t"
- "movl 20(%%rax),%%edi\n\t"
- "popq %%rax\n\t"
- "out %%al,$0xb2\n\t"
- "out %%al,$0x84\n\t"
- "xchgq %%rax,(%%rsp)\n\t"
- "movl %%ebx,4(%%rax)\n\t"
- "movl %%ecx,8(%%rax)\n\t"
- "movl %%edx,12(%%rax)\n\t"
- "movl %%esi,16(%%rax)\n\t"
- "movl %%edi,20(%%rax)\n\t"
- "popq %%rdx\n\t"
- "movl %%edx,0(%%rax)\n\t"
- "pushfq\n\t"
- "popq %%rax\n\t"
- "andl $1,%%eax\n"
- : "=a"(rc)
- : "a"(regs)
- : "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
-#else
- asm volatile("pushl %%eax\n\t"
- "movl 0(%%eax),%%edx\n\t"
- "push %%edx\n\t"
- "movl 4(%%eax),%%ebx\n\t"
- "movl 8(%%eax),%%ecx\n\t"
- "movl 12(%%eax),%%edx\n\t"
- "movl 16(%%eax),%%esi\n\t"
- "movl 20(%%eax),%%edi\n\t"
- "popl %%eax\n\t"
- "out %%al,$0xb2\n\t"
- "out %%al,$0x84\n\t"
- "xchgl %%eax,(%%esp)\n\t"
- "movl %%ebx,4(%%eax)\n\t"
- "movl %%ecx,8(%%eax)\n\t"
- "movl %%edx,12(%%eax)\n\t"
- "movl %%esi,16(%%eax)\n\t"
- "movl %%edi,20(%%eax)\n\t"
- "popl %%edx\n\t"
- "movl %%edx,0(%%eax)\n\t"
- "lahf\n\t"
- "shrl $8,%%eax\n\t"
- "andl $1,%%eax\n"
- : "=a"(rc)
- : "a"(regs)
- : "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
-#endif
+ asm volatile("out %%al,$0xb2\n\t"
+ "out %%al,$0x84\n"
+ : "=a" (regs->eax),
+ "=b" (regs->ebx),
+ "=c" (regs->ecx),
+ "=d" (regs->edx),
+ "=S" (regs->esi),
+ "=D" (regs->edi),
+ CC_OUT(c) (rc)
+ : "a" (regs->eax),
+ "b" (regs->ebx),
+ "c" (regs->ecx),
+ "d" (regs->edx),
+ "S" (regs->esi),
+ "D" (regs->edi));
+
if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
rc = -EINVAL;
--
2.30.2
