diff options
| author |   Thomas Gleixner <tglx@linutronix.de> | 2021-09-08 15:29:29 +0200 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2021-09-14 21:10:03 +0200 |
| commit | 4164a482a5d92c29eaf53d01755103f6bbce38f2 (patch) | |
| tree | 997efc3799555dfc8d172afdc45b959c93f6a412 | |
| parent | x86/fpu/signal: Clarify exception handling in restore_fpregs_from_user() (diff) | |
| download | wireguard-linux-4164a482a5d92c29eaf53d01755103f6bbce38f2.tar.xz wireguard-linux-4164a482a5d92c29eaf53d01755103f6bbce38f2.zip | |
x86/fpu/signal: Move header zeroing out of xsave_to_user_sigframe()
There is no reason to have the header zeroing in the pagefault disabled
region. Do it upfront once.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210908132525.621674721@linutronix.de
| -rw-r--r-- | arch/x86/include/asm/fpu/internal.h | 17 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/signal.c | 12 |
2 files changed, 18 insertions, 11 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 4cfd40dc3cb5..c856ca481546 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -318,9 +318,12 @@ static inline void os_xrstor(struct xregs_state *xstate, u64 mask) * We don't use modified optimization because xrstor/xrstors might track * a different application. * - * We don't use compacted format xsave area for - * backward compatibility for old applications which don't understand - * compacted format of xsave area. + * We don't use compacted format xsave area for backward compatibility for + * old applications which don't understand the compacted format of the + * xsave area. + * + * The caller has to zero buf::header before calling this because XSAVE* + * does not touch the reserved fields in the header. */ static inline int xsave_to_user_sigframe(struct xregs_state __user *buf) { @@ -334,14 +337,6 @@ static inline int xsave_to_user_sigframe(struct xregs_state __user *buf) u32 hmask = mask >> 32; int err; - /* - * Clear the xsave header first, so that reserved fields are - * initialized to zero. - */ - err = __clear_user(&buf->header, sizeof(buf->header)); - if (unlikely(err)) - return -EFAULT; - stac(); XSTATE_OP(XSAVE, buf, lmask, hmask, err); clac(); diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 9bfffdb64c0d..5ca3ce94cf6b 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -189,6 +189,18 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) if (!access_ok(buf, size)) return -EACCES; + + if (use_xsave()) { + struct xregs_state __user *xbuf = buf_fx; + + /* + * Clear the xsave header first, so that reserved fields are + * initialized to zero. + */ + ret = __clear_user(&xbuf->header, sizeof(xbuf->header)); + if (unlikely(ret)) + return ret; + } retry: /* * Load the FPU registers if they are not valid for the current task. |