AuxXxilium/linux_dsm_epyc7002
1
0
Fork 0
mirror of https://github.com/AuxXxilium/linux_dsm_epyc7002.git synced 2025-03-04 15:29:33 +07:00
Code Issues Actions Packages Projects Releases Wiki Activity

x86/fpu/xstate: Fix fpstate_init() for XRSTORS

Browse Source 
In XSAVES mode if fpstate_init() is used to initialize a
task's extended state area, xsave.header.xcomp_bv[63] must
be set. Otherwise, when the task is scheduled, a warning is
triggered from copy_kernel_to_xregs().

One such test case is: setting an invalid extended state
through PTRACE. When xstateregs_set() rejects the syscall
and re-initializes the task's extended state area. This triggers
the warning mentioned above.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <h.peter.anvin@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi V Shankar <ravi.v.shankar@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1468253937-40008-4-git-send-email-fenghua.yu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Yu-cheng Yu 2016-07-11 09:18:56 -07:00 committed by Ingo Molnar
parent 5060b91513
commit 35ac2d7ba7
2 changed files with 14 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/x86/include/asm/fpu/types.h
View File

@ -231,6 +231,12 @@ struct xstate_header {
u64 reserved[6];
} __attribute__((packed));
/*
* xstate_header.xcomp_bv[63] indicates that the extended_state_area
* is in compacted format.
*/
#define XCOMP_BV_COMPACTED_FORMAT ((u64)1 << 63)
/*
* This is our most modern FPU state format, as saved by the XSAVE
* and restored by the XRSTOR instructions.

8
arch/x86/kernel/fpu/core.c
View File

@ -8,6 +8,7 @@
#include <asm/fpu/internal.h>
#include <asm/fpu/regset.h>
#include <asm/fpu/signal.h>
#include <asm/fpu/types.h>
#include <asm/traps.h>
#include <linux/hardirq.h>
@ -229,6 +230,13 @@ void fpstate_init(union fpregs_state *state)
memset(state, 0, fpu_kernel_xstate_size);
/*
* XRSTORS requires that this bit is set in xcomp_bv, or
* it will #GP. Make sure it is replaced after the memset().
*/
if (static_cpu_has(X86_FEATURE_XSAVES))
state->xsave.header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT;
if (static_cpu_has(X86_FEATURE_FXSR))
fpstate_init_fxstate(&state->fxsave);
else