[PATCH 6/6] x86/fpu: Get rid of x87 math exception helpers

From: Borislav Petkov
Date: Tue Apr 05 2016 - 02:30:45 EST


From: Borislav Petkov <bp@xxxxxxx>

... and integrate their functionality into their single user
fpu__exception_code().

No functionality change.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
arch/x86/kernel/fpu/core.c | 44 +++++++++++++-------------------------------
1 file changed, 13 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 1551b28398a4..97027545a72d 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -506,33 +506,6 @@ void fpu__clear(struct fpu *fpu)
* x87 math exception handling:
*/

-static inline unsigned short get_fpu_cwd(struct fpu *fpu)
-{
- if (boot_cpu_has(X86_FEATURE_FXSR)) {
- return fpu->state.fxsave.cwd;
- } else {
- return (unsigned short)fpu->state.fsave.cwd;
- }
-}
-
-static inline unsigned short get_fpu_swd(struct fpu *fpu)
-{
- if (boot_cpu_has(X86_FEATURE_FXSR)) {
- return fpu->state.fxsave.swd;
- } else {
- return (unsigned short)fpu->state.fsave.swd;
- }
-}
-
-static inline unsigned short get_fpu_mxcsr(struct fpu *fpu)
-{
- if (boot_cpu_has(X86_FEATURE_XMM)) {
- return fpu->state.fxsave.mxcsr;
- } else {
- return MXCSR_DEFAULT;
- }
-}
-
int fpu__exception_code(struct fpu *fpu, int trap_nr)
{
int err;
@@ -547,10 +520,15 @@ int fpu__exception_code(struct fpu *fpu, int trap_nr)
* so if this combination doesn't produce any single exception,
* then we have a bad program that isn't synchronizing its FPU usage
* and it will suffer the consequences since we won't be able to
- * fully reproduce the context of the exception
+ * fully reproduce the context of the exception.
*/
- cwd = get_fpu_cwd(fpu);
- swd = get_fpu_swd(fpu);
+ if (boot_cpu_has(X86_FEATURE_FXSR)) {
+ cwd = fpu->state.fxsave.cwd;
+ swd = fpu->state.fxsave.swd;
+ } else {
+ cwd = (unsigned short)fpu->state.fsave.cwd;
+ swd = (unsigned short)fpu->state.fsave.swd;
+ }

err = swd & ~cwd;
} else {
@@ -560,7 +538,11 @@ int fpu__exception_code(struct fpu *fpu, int trap_nr)
* unmasked exception was caught we must mask the exception mask bits
* at 0x1f80, and then use these to mask the exception bits at 0x3f.
*/
- unsigned short mxcsr = get_fpu_mxcsr(fpu);
+ unsigned short mxcsr = MXCSR_DEFAULT;
+
+ if (boot_cpu_has(X86_FEATURE_XMM))
+ mxcsr = fpu->state.fxsave.mxcsr;
+
err = ~(mxcsr >> 7) & mxcsr;
}

--
2.7.3