From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Fenghua Yu <fenghua.yu@intel.com>,
Tony Luck <tony.luck@intel.com>,
Yu-cheng Yu <yu-cheng.yu@intel.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Borislav Petkov <bp@suse.de>,
Peter Zijlstra <peterz@infradead.org>,
Kan Liang <kan.liang@linux.intel.com>
Subject: [patch V2 14/52] x86/fpu: Make copy_xstate_to_kernel() usable for [x]fpregs_get()
Date: Mon, 14 Jun 2021 17:44:22 +0200 [thread overview]
Message-ID: <20210614155355.143470533@linutronix.de> (raw)
In-Reply-To: 20210614154408.673478623@linutronix.de
When xsave with init state optimiziation is used then a component's state
in the task's xsave buffer can be stale when the corresponding feature bit
is not set.
fpregs_get() and xfpregs_get() invoke fpstate_sanitize_xstate() to update
the task's xsave buffer before retrieving the FX or FP state. That's just
duplicated code as copy_xstate_to_kernel() already handles this correctly.
Add a copy mode argument to the function which allows to restrict the state
copy to the FP and SSE features.
Also rename the function to copy_uabi_xstate_to_membuf() so the name
reflects what it is doing.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V2: New patch
---
arch/x86/include/asm/fpu/xstate.h | 12 +++++++++-
arch/x86/kernel/fpu/regset.c | 2 -
arch/x86/kernel/fpu/xstate.c | 42 ++++++++++++++++++++++++++++----------
3 files changed, 42 insertions(+), 14 deletions(-)
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -103,12 +103,20 @@ extern void __init update_regset_xstate_
void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
int using_compacted_format(void);
int xfeature_size(int xfeature_nr);
-struct membuf;
-void copy_xstate_to_kernel(struct membuf to, struct xregs_state *xsave);
int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf);
int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf);
void copy_supervisor_to_kernel(struct xregs_state *xsave);
void copy_dynamic_supervisor_to_kernel(struct xregs_state *xstate, u64 mask);
void copy_kernel_to_dynamic_supervisor(struct xregs_state *xstate, u64 mask);
+enum xstate_copy_mode {
+ XSTATE_COPY_FP,
+ XSTATE_COPY_FX,
+ XSTATE_COPY_XSAVE,
+};
+
+struct membuf;
+void copy_uabi_xstate_to_membuf(struct membuf to, struct xregs_state *xsave,
+ enum xstate_copy_mode mode);
+
#endif
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -94,7 +94,7 @@ int xstateregs_get(struct task_struct *t
fpu__prepare_read(fpu);
- copy_xstate_to_kernel(to, &fpu->state.xsave);
+ copy_uabi_xstate_to_membuf(to, &fpu->state.xsave, XSTATE_COPY_XSAVE);
return 0;
}
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1062,14 +1062,20 @@ static void copy_feature(bool from_xstat
membuf_write(to, from_xstate ? xstate : init_xstate, size);
}
-/*
- * Convert from kernel XSAVE or XSAVES compacted format to UABI
- * non-compacted format and copy to a kernel-space ptrace buffer.
+/**
+ * copy_uabi_xstate_to_membuf - Copy kernel saved xstate to a UABI buffer
+ * @to: membuf descriptor
+ * @xsave: The kernel xstate buffer to copy from
+ * @copy_mode: The requested copy mode
*
- * It supports partial copy but pos always starts from zero. This is called
- * from xstateregs_get() and there we check the CPU has XSAVE.
+ * Converts from kernel XSAVE or XSAVES compacted format to UABI conforming
+ * format, i.e. from the kernel internal hardware dependent storage format
+ * to the requested @mode. UABI XSTATE is always uncompacted!
+ *
+ * It supports partial copy but @to.pos always starts from zero.
*/
-void copy_xstate_to_kernel(struct membuf to, struct xregs_state *xsave)
+void copy_uabi_xstate_to_membuf(struct membuf to, struct xregs_state *xsave,
+ enum xstate_copy_mode copy_mode)
{
const unsigned int off_mxcsr = offsetof(struct fxregs_state, mxcsr);
struct xregs_state *xinit = &init_fpstate.xsave;
@@ -1077,12 +1083,22 @@ void copy_xstate_to_kernel(struct membuf
unsigned int zerofrom;
int i;
- /*
- * The destination is a ptrace buffer; we put in only user xstates:
- */
- memset(&header, 0, sizeof(header));
header.xfeatures = xsave->header.xfeatures;
- header.xfeatures &= xfeatures_mask_user();
+
+ /* Mask out the feature bits depending on copy mode */
+ switch (copy_mode) {
+ case XSTATE_COPY_FP:
+ header.xfeatures &= XFEATURE_MASK_FP;
+ break;
+
+ case XSTATE_COPY_FX:
+ header.xfeatures &= XFEATURE_MASK_FP | XFEATURE_MASK_SSE;
+ break;
+
+ case XSTATE_COPY_XSAVE:
+ header.xfeatures &= xfeatures_mask_user();
+ break;
+ }
/* Copy FP state up to MXCSR */
copy_feature(header.xfeatures & XFEATURE_MASK_FP, &to, &xsave->i387,
@@ -1103,6 +1119,9 @@ void copy_xstate_to_kernel(struct membuf
&to, &xsave->i387.xmm_space, &xinit->i387.xmm_space,
16 * 16);
+ if (copy_mode != XSTATE_COPY_XSAVE)
+ goto out;
+
/* Zero the padding area */
membuf_zero(&to, sizeof(xsave->i387.padding));
@@ -1144,6 +1163,7 @@ void copy_xstate_to_kernel(struct membuf
zerofrom = xstate_offsets[i] + xstate_sizes[i];
}
+out:
if (to.left)
membuf_zero(&to, to.left);
}
next prev parent reply other threads:[~2021-06-14 16:38 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-14 15:44 [patch V2 00/52] x86/fpu: Spring cleaning and PKRU sanitizing Thomas Gleixner
2021-06-14 15:44 ` [patch V2 01/52] x86/fpu: Make init_fpstate correct with optimized XSAVE Thomas Gleixner
2021-06-14 19:15 ` Borislav Petkov
2021-06-14 15:44 ` [patch V2 02/52] x86/fpu: Fix copy_xstate_to_kernel() gap handling Thomas Gleixner
2021-06-15 11:07 ` Borislav Petkov
2021-06-15 12:47 ` Thomas Gleixner
2021-06-15 12:59 ` Borislav Petkov
2021-06-16 22:02 ` Thomas Gleixner
2021-06-14 15:44 ` [patch V2 03/52] x86/pkeys: Revert a5eff7259790 ("x86/pkeys: Add PKRU value to init_fpstate") Thomas Gleixner
2021-06-15 13:15 ` Borislav Petkov
2021-06-14 15:44 ` [patch V2 04/52] x86/fpu: Mark various FPU states __ro_after_init Thomas Gleixner
2021-06-14 15:44 ` [patch V2 05/52] x86/fpu: Remove unused get_xsave_field_ptr() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 06/52] x86/fpu: Move inlines where they belong Thomas Gleixner
2021-06-14 15:44 ` [patch V2 07/52] x86/fpu: Limit xstate copy size in xstateregs_set() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 08/52] x86/fpu: Sanitize xstateregs_set() Thomas Gleixner
2021-06-15 17:40 ` Borislav Petkov
2021-06-15 21:32 ` Thomas Gleixner
2021-06-14 15:44 ` [patch V2 09/52] x86/fpu: Reject invalid MXCSR values in copy_kernel_to_xstate() Thomas Gleixner
2021-06-16 15:02 ` Borislav Petkov
2021-06-16 23:51 ` Thomas Gleixner
2021-06-14 15:44 ` [patch V2 10/52] x86/fpu: Simplify PTRACE_GETREGS code Thomas Gleixner
2021-06-14 15:44 ` [patch V2 11/52] x86/fpu: Rewrite xfpregs_set() Thomas Gleixner
2021-06-16 15:22 ` Borislav Petkov
2021-06-14 15:44 ` [patch V2 12/52] x86/fpu: Fail ptrace() requests that try to set invalid MXCSR values Thomas Gleixner
2021-06-16 15:31 ` Borislav Petkov
2021-06-14 15:44 ` [patch V2 13/52] x86/fpu: Clean up fpregs_set() Thomas Gleixner
2021-06-16 15:42 ` Borislav Petkov
2021-06-14 15:44 ` Thomas Gleixner [this message]
2021-06-16 16:13 ` [patch V2 14/52] x86/fpu: Make copy_xstate_to_kernel() usable for [x]fpregs_get() Borislav Petkov
2021-06-17 12:42 ` Thomas Gleixner
2021-06-14 15:44 ` [patch V2 15/52] x86/fpu: Use copy_uabi_xstate_to_membuf() in xfpregs_get() Thomas Gleixner
2021-06-17 8:59 ` Borislav Petkov
2021-06-18 11:19 ` Borislav Petkov
2021-06-18 13:25 ` [PATCH] selftests/x86/ptrace_syscall: Add a PTRACE_GETFPREGS test Borislav Petkov
2021-06-14 15:44 ` [patch V2 16/52] x86/fpu: Use copy_uabi_xstate_to_membuf() in fpregs_get() Thomas Gleixner
2021-06-17 11:50 ` Borislav Petkov
2021-06-17 12:43 ` Thomas Gleixner
2021-06-14 15:44 ` [patch V2 17/52] x86/fpu: Remove fpstate_sanitize_xstate() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 18/52] x86/fpu: Get rid of using_compacted_format() Thomas Gleixner
2021-06-17 11:59 ` Borislav Petkov
2021-06-14 15:44 ` [patch V2 19/52] x86/kvm: Avoid looking up PKRU in XSAVE buffer Thomas Gleixner
2021-06-17 12:09 ` Borislav Petkov
2021-06-14 15:44 ` [patch V2 20/52] x86/fpu: Cleanup arch_set_user_pkey_access() Thomas Gleixner
2021-06-17 12:22 ` Borislav Petkov
2021-06-17 12:49 ` Thomas Gleixner
2021-06-14 15:44 ` [patch V2 21/52] x86/fpu: Get rid of copy_supervisor_to_kernel() Thomas Gleixner
2021-06-17 12:41 ` Borislav Petkov
2021-06-14 15:44 ` [patch V2 22/52] x86/fpu: Rename copy_xregs_to_kernel() and copy_kernel_to_xregs() Thomas Gleixner
2021-06-17 12:48 ` Borislav Petkov
2021-06-14 15:44 ` [patch V2 23/52] x86/fpu: Rename copy_user_to_xregs() and copy_xregs_to_user() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 24/52] x86/fpu: Rename fxregs related copy functions Thomas Gleixner
2021-06-14 15:44 ` [patch V2 25/52] x86/fpu: Rename fregs " Thomas Gleixner
2021-06-14 15:44 ` [patch V2 26/52] x86/fpu: Rename xstate copy functions which are related to UABI Thomas Gleixner
2021-06-14 15:44 ` [patch V2 27/52] x86/fpu: Deduplicate copy_uabi_from_user/kernel_to_xstate() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 28/52] x86/fpu: Rename copy_fpregs_to_fpstate() to save_fpregs_to_fpstate() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 29/52] x86/fpu: Rename copy_kernel_to_fpregs() to restore_fpregs_from_kernel() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 30/52] x86/fpu: Rename initstate copy functions Thomas Gleixner
2021-06-14 15:44 ` [patch V2 31/52] x86/fpu: Rename "dynamic" XSTATEs to "independent" Thomas Gleixner
2021-06-14 15:44 ` [patch V2 32/52] x86/fpu/xstate: Sanitize handling of independent features Thomas Gleixner
2021-06-16 20:04 ` Liang, Kan
2021-06-17 7:15 ` Thomas Gleixner
2021-06-14 15:44 ` [patch V2 33/52] x86/pkeys: Move read_pkru() and write_pkru() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 34/52] x86/fpu: Differentiate "copy" versus "move" of fpregs Thomas Gleixner
2021-06-18 12:21 ` Thomas Gleixner
2021-06-14 15:44 ` [patch V2 35/52] x86/cpu: Sanitize X86_FEATURE_OSPKE Thomas Gleixner
2021-06-14 15:44 ` [patch V2 36/52] x86/pkru: Provide pkru_get_init_value() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 37/52] x86/pkru: Provide pkru_write_default() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 38/52] x86/cpu: Write the default PKRU value when enabling PKE Thomas Gleixner
2021-06-14 15:44 ` [patch V2 39/52] x86/fpu: Use pkru_write_default() in copy_init_fpstate_to_fpregs() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 40/52] x86/fpu: Rename fpu__clear_all() to fpu_flush_thread() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 41/52] x86/fpu: Clean up the fpu__clear() variants Thomas Gleixner
2021-06-14 15:44 ` [patch V2 42/52] x86/fpu: Rename __fpregs_load_activate() to fpregs_restore_userregs() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 43/52] x86/fpu: Move FXSAVE_LEAK quirk info __copy_kernel_to_fpregs() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 44/52] x86/fpu: Rename xfeatures_mask_user() to xfeatures_mask_uabi() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 45/52] x86/fpu: Dont restore PKRU in fpregs_restore_userspace() Thomas Gleixner
2021-06-16 0:52 ` Yu, Yu-cheng
2021-06-16 8:56 ` Thomas Gleixner
2021-06-14 15:44 ` [patch V2 46/52] x86/fpu: Add PKRU storage outside of task XSAVE buffer Thomas Gleixner
2021-06-14 15:44 ` [patch V2 47/52] x86/fpu: Hook up PKRU into ptrace() Thomas Gleixner
2021-06-14 19:29 ` [patch V2-A " Thomas Gleixner
2021-06-14 15:44 ` [patch V2 48/52] x86/fpu: Mask PKRU from kernel XRSTOR[S] operations Thomas Gleixner
2021-06-14 15:44 ` [patch V2 49/52] x86/fpu: Remove PKRU handling from switch_fpu_finish() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 50/52] x86/fpu: Dont store PKRU in xstate in fpu_reset_fpstate() Thomas Gleixner
2021-06-14 15:44 ` [patch V2 51/52] x86/pkru: Remove xstate fiddling from write_pkru() Thomas Gleixner
2021-06-14 15:45 ` [patch V2 52/52] x86/fpu: Mark init_fpstate __ro_after_init Thomas Gleixner
2021-06-14 20:15 ` [patch] x86/fpu: x86/fpu: Preserve supervisor states in sanitize_restored_user_xstate() Thomas Gleixner
2021-06-16 0:50 ` [patch V2 00/52] x86/fpu: Spring cleaning and PKRU sanitizing Yu, Yu-cheng
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