The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: d6d6d50f1e801a790a242c80eeda261e36c43b7b
Gitweb: https://git.kernel.org/tip/d6d6d50f1e801a790a242c80eeda261e36c43b7b
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Mon, 28 Mar 2022 20:43:21 +02:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Wed, 30 Mar 2022 12:04:09 +02:00
x86/fpu/xstate: Consolidate size calculations
Use the offset calculation to do the size calculation which avoids yet
another series of CPUID instructions for each invocation.
[ Fix the FP/SSE only case which missed to take the xstate
header into account, as
Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> ]
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lore.kernel.org/r/87o81pgbp2.ffs@tglx
---
arch/x86/kernel/fpu/xstate.c | 49 +++++------------------------------
1 file changed, 8 insertions(+), 41 deletions(-)
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 5ac934b..39e1c86 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -385,25 +385,6 @@ static void __init setup_init_fpu_buf(void)
fxsave(&init_fpstate.regs.fxsave);
}
-static int xfeature_uncompacted_offset(int xfeature_nr)
-{
- u32 eax, ebx, ecx, edx;
-
- /*
- * Only XSAVES supports supervisor states and it uses compacted
- * format. Checking a supervisor state's uncompacted offset is
- * an error.
- */
- if (XFEATURE_MASK_SUPERVISOR_ALL & BIT_ULL(xfeature_nr)) {
- WARN_ONCE(1, "No fixed offset for xstate %d\n", xfeature_nr);
- return -1;
- }
-
- CHECK_XFEATURE(xfeature_nr);
- cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx);
- return ebx;
-}
-
int xfeature_size(int xfeature_nr)
{
u32 eax, ebx, ecx, edx;
@@ -581,29 +562,15 @@ static bool __init check_xstate_against_struct(int nr)
static unsigned int xstate_calculate_size(u64 xfeatures, bool compacted)
{
- unsigned int size = FXSAVE_SIZE + XSAVE_HDR_SIZE;
- int i;
+ unsigned int topmost = fls64(xfeatures) - 1;
+ unsigned int offset = xstate_offsets[topmost];
- for_each_extended_xfeature(i, xfeatures) {
- /* Align from the end of the previous feature */
- if (xfeature_is_aligned64(i))
- size = ALIGN(size, 64);
- /*
- * In compacted format the enabled features are packed,
- * i.e. disabled features do not occupy space.
- *
- * In non-compacted format the offsets are fixed and
- * disabled states still occupy space in the memory buffer.
- */
- if (!compacted)
- size = xfeature_uncompacted_offset(i);
- /*
- * Add the feature size even for non-compacted format
- * to make the end result correct
- */
- size += xfeature_size(i);
- }
- return size;
+ if (topmost <= XFEATURE_SSE)
+ return sizeof(struct xregs_state);
+
+ if (compacted)
+ offset = xfeature_get_offset(xfeatures, topmost);
+ return offset + xstate_sizes[topmost];
}
/*
|