6.12-stable review patch. If anyone has any objections, please let me know.
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From: Chang S. Bae chang.seok.bae@intel.com
commit 64e54461ab6e8524a8de4e63b7d1a3e4481b5cf3 upstream.
Currently, saving register states in the signal frame, the legacy feature bits are always set in xregs_state->header->xfeatures. This code sequence can be generalized for reuse in similar cases.
Refactor the logic to ensure a consistent approach across similar usages.
Signed-off-by: Chang S. Bae chang.seok.bae@intel.com Signed-off-by: Ingo Molnar mingo@kernel.org Cc: Andy Lutomirski luto@kernel.org Cc: H. Peter Anvin hpa@zytor.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Oleg Nesterov oleg@redhat.com Link: https://lore.kernel.org/r/20250416021720.12305-8-chang.seok.bae@intel.com Cc: Ben Hutchings ben@decadent.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kernel/fpu/signal.c | 11 +---------- arch/x86/kernel/fpu/xstate.h | 13 +++++++++++++ 2 files changed, 14 insertions(+), 10 deletions(-)
--- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -119,7 +119,6 @@ static inline bool save_xstate_epilog(vo { struct xregs_state __user *x = buf; struct _fpx_sw_bytes sw_bytes = {}; - u32 xfeatures; int err;
/* Setup the bytes not touched by the [f]xsave and reserved for SW. */ @@ -133,12 +132,6 @@ static inline bool save_xstate_epilog(vo (__u32 __user *)(buf + fpstate->user_size));
/* - * Read the xfeatures which we copied (directly from the cpu or - * from the state in task struct) to the user buffers. - */ - err |= __get_user(xfeatures, (__u32 __user *)&x->header.xfeatures); - - /* * For legacy compatible, we always set FP/SSE bits in the bit * vector while saving the state to the user context. This will * enable us capturing any changes(during sigreturn) to @@ -149,9 +142,7 @@ static inline bool save_xstate_epilog(vo * header as well as change any contents in the memory layout. * xrestore as part of sigreturn will capture all the changes. */ - xfeatures |= XFEATURE_MASK_FPSSE; - - err |= __put_user(xfeatures, (__u32 __user *)&x->header.xfeatures); + err |= set_xfeature_in_sigframe(x, XFEATURE_MASK_FPSSE);
return !err; } --- a/arch/x86/kernel/fpu/xstate.h +++ b/arch/x86/kernel/fpu/xstate.h @@ -69,6 +69,19 @@ static inline u64 xfeatures_mask_indepen return fpu_kernel_cfg.independent_features; }
+static inline int set_xfeature_in_sigframe(struct xregs_state __user *xbuf, u64 mask) +{ + u64 xfeatures; + int err; + + /* Read the xfeatures value already saved in the user buffer */ + err = __get_user(xfeatures, &xbuf->header.xfeatures); + xfeatures |= mask; + err |= __put_user(xfeatures, &xbuf->header.xfeatures); + + return err; +} + /* * Update the value of PKRU register that was already pushed onto the signal frame. */