From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: bp@suse.de, luto@kernel.org, tglx@linutronix.de,
mingo@kernel.org, x86@kernel.org
Cc: len.brown@intel.com, dave.hansen@intel.com, jing2.liu@intel.com,
ravi.v.shankar@intel.com, linux-kernel@vger.kernel.org,
chang.seok.bae@intel.com
Subject: [PATCH v3 12/21] x86/fpu/xstate: Update xstate context copy function to support dynamic buffer
Date: Wed, 23 Dec 2020 07:57:08 -0800 [thread overview]
Message-ID: <20201223155717.19556-13-chang.seok.bae@intel.com> (raw)
In-Reply-To: <20201223155717.19556-1-chang.seok.bae@intel.com>
ptrace() and signal return paths use xstate context copy functions. They
allow callers to read (or write) xstate values in the target's buffer. With
dynamic user states, a component's position in the buffer may vary and the
initial value is not always stored in init_fpstate.
Change the helpers to find a component's offset accordingly.
When copying an initial value, explicitly check the init_fpstate coverage.
If not found, reset the memory in the destination. Otherwise, copy values
from init_fpstate.
No functional change until the kernel supports dynamic user states.
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from v2:
* Updated the changelog with task->fpu removed. (Boris Petkov)
---
arch/x86/kernel/fpu/xstate.c | 55 +++++++++++++++++++++++++++---------
1 file changed, 41 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 6b863b2ca405..1d7d0cce6cc5 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -248,12 +248,14 @@ void fpstate_sanitize_xstate(struct fpu *fpu)
if (!(xfeatures & XFEATURE_MASK_SSE))
memset(&fx->xmm_space[0], 0, 256);
+ /* Make sure 'xfeatures' to be a subset of fpu->state_mask */
+ xfeatures = ((xfeatures_mask_user() & fpu->state_mask) & ~xfeatures);
/*
* First two features are FPU and SSE, which above we handled
* in a special way already:
*/
feature_bit = 0x2;
- xfeatures = (xfeatures_mask_user() & ~xfeatures) >> 2;
+ xfeatures >>= 0x2;
/*
* Update all the remaining memory layouts according to their
@@ -262,12 +264,15 @@ void fpstate_sanitize_xstate(struct fpu *fpu)
*/
while (xfeatures) {
if (xfeatures & 0x1) {
- int offset = xstate_comp_offsets[feature_bit];
- int size = xstate_sizes[feature_bit];
-
- memcpy((void *)xsave + offset,
- (void *)&init_fpstate.xsave + offset,
- size);
+ unsigned int offset = get_xstate_comp_offset(fpu, feature_bit);
+ unsigned int size = xstate_sizes[feature_bit];
+
+ if (get_init_fpstate_mask() & BIT_ULL(feature_bit))
+ memcpy((void *)xsave + offset,
+ (void *)&init_fpstate.xsave + offset,
+ size);
+ else
+ memset((void *)xsave + offset, 0, size);
}
xfeatures >>= 1;
@@ -1232,7 +1237,10 @@ static void fill_gap(struct membuf *to, unsigned *last, unsigned offset)
{
if (*last >= offset)
return;
- membuf_write(to, (void *)&init_fpstate.xsave + *last, offset - *last);
+ if (offset <= get_init_fpstate_size())
+ membuf_write(to, (void *)&init_fpstate.xsave + *last, offset - *last);
+ else
+ membuf_zero(to, offset - *last);
*last = offset;
}
@@ -1240,7 +1248,10 @@ static void copy_part(struct membuf *to, unsigned *last, unsigned offset,
unsigned size, void *from)
{
fill_gap(to, last, offset);
- membuf_write(to, from, size);
+ if (from)
+ membuf_write(to, from, size);
+ else
+ membuf_zero(to, size);
*last = offset + size;
}
@@ -1292,12 +1303,22 @@ void copy_xstate_to_kernel(struct membuf to, struct fpu *fpu)
sizeof(header), &header);
for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
+ u64 mask = BIT_ULL(i);
+ void *src;
/*
- * Copy only in-use xstates:
+ * Copy only in-use xstate at first. If the feature is enabled,
+ * find the init value, whether stored in init_fpstate or simply
+ * zeros, and then copy them.
*/
- if ((header.xfeatures >> i) & 1) {
- void *src = __raw_xsave_addr(fpu, i);
-
+ if (header.xfeatures & mask) {
+ src = __raw_xsave_addr(fpu, i);
+ copy_part(&to, &last, xstate_offsets[i],
+ xstate_sizes[i], src);
+ } else if (xfeatures_mask_user() & mask) {
+ if (get_init_fpstate_mask() & mask)
+ src = (void *)&init_fpstate.xsave + last;
+ else
+ src = NULL;
copy_part(&to, &last, xstate_offsets[i],
xstate_sizes[i], src);
}
@@ -1331,6 +1352,9 @@ int copy_kernel_to_xstate(struct fpu *fpu, const void *kbuf)
if (hdr.xfeatures & mask) {
void *dst = __raw_xsave_addr(fpu, i);
+ if (!dst)
+ continue;
+
offset = xstate_offsets[i];
size = xstate_sizes[i];
@@ -1388,6 +1412,9 @@ int copy_user_to_xstate(struct fpu *fpu, const void __user *ubuf)
if (hdr.xfeatures & mask) {
void *dst = __raw_xsave_addr(fpu, i);
+ if (!dst)
+ continue;
+
offset = xstate_offsets[i];
size = xstate_sizes[i];
@@ -1470,7 +1497,7 @@ void copy_supervisor_to_kernel(struct fpu *fpu)
continue;
/* Move xfeature 'i' into its normal location */
- memmove(xbuf + xstate_comp_offsets[i],
+ memmove(xbuf + get_xstate_comp_offset(fpu, i),
xbuf + xstate_supervisor_only_offsets[i],
xstate_sizes[i]);
}
--
2.17.1
next prev parent reply other threads:[~2020-12-23 16:03 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-23 15:56 [PATCH v3 00/21] x86: Support Intel Advanced Matrix Extensions Chang S. Bae
2020-12-23 15:56 ` [PATCH v3 01/21] x86/fpu/xstate: Modify initialization helper to handle both static and dynamic buffers Chang S. Bae
2021-01-15 12:40 ` Borislav Petkov
2020-12-23 15:56 ` [PATCH v3 02/21] x86/fpu/xstate: Modify state copy helpers " Chang S. Bae
2021-01-15 12:50 ` Borislav Petkov
2021-01-19 18:50 ` Bae, Chang Seok
2021-01-20 20:53 ` Borislav Petkov
2021-01-20 21:12 ` Bae, Chang Seok
2020-12-23 15:56 ` [PATCH v3 03/21] x86/fpu/xstate: Modify address finders " Chang S. Bae
2021-01-15 13:06 ` Borislav Petkov
2020-12-23 15:57 ` [PATCH v3 04/21] x86/fpu/xstate: Modify context switch helpers " Chang S. Bae
2021-01-15 13:18 ` Borislav Petkov
2021-01-19 18:49 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 05/21] x86/fpu/xstate: Add a new variable to indicate dynamic user states Chang S. Bae
2021-01-15 13:39 ` Borislav Petkov
2021-01-15 19:47 ` Bae, Chang Seok
2021-01-19 15:57 ` Borislav Petkov
2021-01-19 18:57 ` Bae, Chang Seok
2021-01-22 10:56 ` Borislav Petkov
2021-01-27 1:23 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 06/21] x86/fpu/xstate: Calculate and remember dynamic xstate buffer sizes Chang S. Bae
2021-01-22 11:44 ` Borislav Petkov
2021-01-27 1:23 ` Bae, Chang Seok
2021-01-27 9:38 ` Borislav Petkov
2021-02-03 2:54 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 07/21] x86/fpu/xstate: Introduce helpers to manage dynamic xstate buffers Chang S. Bae
2021-01-26 20:17 ` Borislav Petkov
2021-01-27 1:23 ` Bae, Chang Seok
2021-01-27 10:41 ` Borislav Petkov
2021-02-03 4:10 ` Bae, Chang Seok
2021-02-04 13:10 ` Borislav Petkov
2021-02-03 4:10 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 08/21] x86/fpu/xstate: Define the scope of the initial xstate data Chang S. Bae
2021-02-08 12:33 ` Borislav Petkov
2021-02-08 18:53 ` Bae, Chang Seok
2021-02-09 12:49 ` Borislav Petkov
2021-02-09 15:38 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 09/21] x86/fpu/xstate: Introduce wrapper functions to organize xstate buffer access Chang S. Bae
2021-02-08 12:33 ` Borislav Petkov
2021-02-09 15:50 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 10/21] x86/fpu/xstate: Update xstate save function to support dynamic xstate Chang S. Bae
2021-01-07 8:41 ` Liu, Jing2
2021-01-07 18:40 ` Bae, Chang Seok
2021-01-12 2:52 ` Liu, Jing2
2021-01-15 4:59 ` Bae, Chang Seok
2021-01-15 5:45 ` Liu, Jing2
2021-02-08 12:33 ` Borislav Petkov
2021-02-09 15:48 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 11/21] x86/fpu/xstate: Update xstate buffer address finder " Chang S. Bae
2021-02-19 15:00 ` Borislav Petkov
2021-02-19 19:19 ` Bae, Chang Seok
2020-12-23 15:57 ` Chang S. Bae [this message]
2020-12-23 15:57 ` [PATCH v3 13/21] x86/fpu/xstate: Expand dynamic context switch buffer on first use Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 14/21] x86/fpu/xstate: Support ptracer-induced xstate buffer expansion Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 15/21] x86/fpu/xstate: Extend the table to map xstate components with features Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 16/21] x86/cpufeatures/amx: Enumerate Advanced Matrix Extension (AMX) feature bits Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 17/21] x86/fpu/amx: Define AMX state components and have it used for boot-time checks Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 18/21] x86/fpu/amx: Enable the AMX feature in 64-bit mode Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 19/21] selftest/x86/amx: Include test cases for the AMX state management Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 20/21] x86/fpu/xstate: Support dynamic user state in the signal handling path Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 21/21] x86/fpu/xstate: Introduce boot-parameters to control some state component support Chang S. Bae
2020-12-23 18:37 ` Randy Dunlap
2021-01-14 21:31 ` Bae, Chang Seok
2021-01-14 21:31 ` [PATCH v3 00/21] x86: Support Intel Advanced Matrix Extensions Bae, Chang Seok
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