diff options
Diffstat (limited to 'arch/x86/kernel/xsave.c')
| -rw-r--r-- | arch/x86/kernel/xsave.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index 07713d64deb..9abac8a9d82 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -95,7 +95,9 @@ int save_i387_xstate(void __user *buf) * Start with clearing the user buffer. This will present a * clean context for the bytes not touched by the fxsave/xsave. */ - __clear_user(buf, sig_xstate_size); + err = __clear_user(buf, sig_xstate_size); + if (err) + return err; if (task_thread_info(tsk)->status & TS_XSAVE) err = xsave_user(buf); @@ -114,6 +116,8 @@ int save_i387_xstate(void __user *buf) if (task_thread_info(tsk)->status & TS_XSAVE) { struct _fpstate __user *fx = buf; + struct _xstate __user *x = buf; + u64 xstate_bv; err = __copy_to_user(&fx->sw_reserved, &fx_sw_reserved, sizeof(struct _fpx_sw_bytes)); @@ -121,6 +125,31 @@ int save_i387_xstate(void __user *buf) err |= __put_user(FP_XSTATE_MAGIC2, (__u32 __user *) (buf + sig_xstate_size - FP_XSTATE_MAGIC2_SIZE)); + + /* + * Read the xstate_bv which we copied (directly from the cpu or + * from the state in task struct) to the user buffers and + * set the FP/SSE bits. + */ + err |= __get_user(xstate_bv, &x->xstate_hdr.xstate_bv); + + /* + * 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 + * the FP/SSE bits by the legacy applications which don't touch + * xstate_bv in the xsave header. + * + * xsave aware apps can change the xstate_bv in the xsave + * header as well as change any contents in the memory layout. + * xrestore as part of sigreturn will capture all the changes. + */ + xstate_bv |= XSTATE_FPSSE; + + err |= __put_user(xstate_bv, &x->xstate_hdr.xstate_bv); + + if (err) + return err; } return 1; @@ -272,7 +301,7 @@ void __cpuinit xsave_init(void) /* * setup the xstate image representing the init state */ -void setup_xstate_init(void) +static void __init setup_xstate_init(void) { init_xstate_buf = alloc_bootmem(xstate_size); init_xstate_buf->i387.mxcsr = MXCSR_DEFAULT; |