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-rw-r--r--Documentation/kernel-parameters.txt15
-rw-r--r--arch/x86/include/asm/alternative.h14
-rw-r--r--arch/x86/include/asm/fpu-internal.h9
-rw-r--r--arch/x86/include/asm/processor.h4
-rw-r--r--arch/x86/include/asm/xsave.h223
-rw-r--r--arch/x86/kernel/cpu/common.c8
-rw-r--r--arch/x86/kernel/i387.c2
-rw-r--r--arch/x86/kernel/process.c1
-rw-r--r--arch/x86/kernel/xsave.c118
9 files changed, 324 insertions, 70 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a8eb6afce6a4..5ae8608ca9f5 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2200,6 +2200,21 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
and restore using xsave. The kernel will fallback to
enabling legacy floating-point and sse state.
+ noxsaveopt [X86] Disables xsaveopt used in saving x86 extended
+ register states. The kernel will fall back to use
+ xsave to save the states. By using this parameter,
+ performance of saving the states is degraded because
+ xsave doesn't support modified optimization while
+ xsaveopt supports it on xsaveopt enabled systems.
+
+ noxsaves [X86] Disables xsaves and xrstors used in saving and
+ restoring x86 extended register state in compacted
+ form of xsave area. The kernel will fall back to use
+ xsaveopt and xrstor to save and restore the states
+ in standard form of xsave area. By using this
+ parameter, xsave area per process might occupy more
+ memory on xsaves enabled systems.
+
eagerfpu= [X86]
on enable eager fpu restore
off disable eager fpu restore
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 0a3f9c9f98d5..473bdbee378a 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -161,6 +161,20 @@ static inline int alternatives_text_reserved(void *start, void *end)
asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
: : "i" (0), ## input)
+/*
+ * This is similar to alternative_input. But it has two features and
+ * respective instructions.
+ *
+ * If CPU has feature2, newinstr2 is used.
+ * Otherwise, if CPU has feature1, newinstr1 is used.
+ * Otherwise, oldinstr is used.
+ */
+#define alternative_input_2(oldinstr, newinstr1, feature1, newinstr2, \
+ feature2, input...) \
+ asm volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, \
+ newinstr2, feature2) \
+ : : "i" (0), ## input)
+
/* Like alternative_input, but with a single output argument */
#define alternative_io(oldinstr, newinstr, feature, output, input...) \
asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index e3b85422cf12..412ececa00b9 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -508,9 +508,12 @@ static inline void user_fpu_begin(void)
static inline void __save_fpu(struct task_struct *tsk)
{
- if (use_xsave())
- xsave_state(&tsk->thread.fpu.state->xsave, -1);
- else
+ if (use_xsave()) {
+ if (unlikely(system_state == SYSTEM_BOOTING))
+ xsave_state_booting(&tsk->thread.fpu.state->xsave, -1);
+ else
+ xsave_state(&tsk->thread.fpu.state->xsave, -1);
+ } else
fpu_fxsave(&tsk->thread.fpu);
}
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index ee30b9f0b91c..eb71ec794732 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -385,8 +385,8 @@ struct bndcsr_struct {
struct xsave_hdr_struct {
u64 xstate_bv;
- u64 reserved1[2];
- u64 reserved2[5];
+ u64 xcomp_bv;
+ u64 reserved[6];
} __attribute__((packed));
struct xsave_struct {
diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index d949ef28c48b..7e7a79ada658 100644
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -52,24 +52,170 @@ extern void xsave_init(void);
extern void update_regset_xstate_info(unsigned int size, u64 xstate_mask);
extern int init_fpu(struct task_struct *child);
-static inline int fpu_xrstor_checking(struct xsave_struct *fx)
+/* These macros all use (%edi)/(%rdi) as the single memory argument. */
+#define XSAVE ".byte " REX_PREFIX "0x0f,0xae,0x27"
+#define XSAVEOPT ".byte " REX_PREFIX "0x0f,0xae,0x37"
+#define XSAVES ".byte " REX_PREFIX "0x0f,0xc7,0x2f"
+#define XRSTOR ".byte " REX_PREFIX "0x0f,0xae,0x2f"
+#define XRSTORS ".byte " REX_PREFIX "0x0f,0xc7,0x1f"
+
+#define xstate_fault ".section .fixup,\"ax\"\n" \
+ "3: movl $-1,%[err]\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE(1b, 3b) \
+ : [err] "=r" (err)
+
+/*
+ * This function is called only during boot time when x86 caps are not set
+ * up and alternative can not be used yet.
+ */
+static inline int xsave_state_booting(struct xsave_struct *fx, u64 mask)
{
- int err;
+ u32 lmask = mask;
+ u32 hmask = mask >> 32;
+ int err = 0;
+
+ WARN_ON(system_state != SYSTEM_BOOTING);
+
+ if (boot_cpu_has(X86_FEATURE_XSAVES))
+ asm volatile("1:"XSAVES"\n\t"
+ "2:\n\t"
+ : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+ : "memory");
+ else
+ asm volatile("1:"XSAVE"\n\t"
+ "2:\n\t"
+ : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+ : "memory");
+
+ asm volatile(xstate_fault
+ : "0" (0)
+ : "memory");
+
+ return err;
+}
+
+/*
+ * This function is called only during boot time when x86 caps are not set
+ * up and alternative can not be used yet.
+ */
+static inline int xrstor_state_booting(struct xsave_struct *fx, u64 mask)
+{
+ u32 lmask = mask;
+ u32 hmask = mask >> 32;
+ int err = 0;
+
+ WARN_ON(system_state != SYSTEM_BOOTING);
- asm volatile("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- _ASM_EXTABLE(1b, 3b)
- : [err] "=r" (err)
- : "D" (fx), "m" (*fx), "a" (-1), "d" (-1), "0" (0)
+ if (boot_cpu_has(X86_FEATURE_XSAVES))
+ asm volatile("1:"XRSTORS"\n\t"
+ "2:\n\t"
+ : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+ : "memory");
+ else
+ asm volatile("1:"XRSTOR"\n\t"
+ "2:\n\t"
+ : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+ : "memory");
+
+ asm volatile(xstate_fault
+ : "0" (0)
+ : "memory");
+
+ return err;
+}
+
+/*
+ * Save processor xstate to xsave area.
+ */
+static inline int xsave_state(struct xsave_struct *fx, u64 mask)
+{
+ u32 lmask = mask;
+ u32 hmask = mask >> 32;
+ int err = 0;
+
+ /*
+ * If xsaves is enabled, xsaves replaces xsaveopt because
+ * it supports compact format and supervisor states in addition to
+ * modified optimization in xsaveopt.
+ *
+ * Otherwise, if xsaveopt is enabled, xsaveopt replaces xsave
+ * because xsaveopt supports modified optimization which is not
+ * supported by xsave.
+ *
+ * If none of xsaves and xsaveopt is enabled, use xsave.
+ */
+ alternative_input_2(
+ "1:"XSAVE,
+ "1:"XSAVEOPT,
+ X86_FEATURE_XSAVEOPT,
+ "1:"XSAVES,
+ X86_FEATURE_XSAVES,
+ [fx] "D" (fx), "a" (lmask), "d" (hmask) :
+ "memory");
+ asm volatile("2:\n\t"
+ xstate_fault
+ : "0" (0)
: "memory");
return err;
}
+/*
+ * Restore processor xstate from xsave area.
+ */
+static inline int xrstor_state(struct xsave_struct *fx, u64 mask)
+{
+ int err = 0;
+ u32 lmask = mask;
+ u32 hmask = mask >> 32;
+
+ /*
+ * Use xrstors to restore context if it is enabled. xrstors supports
+ * compacted format of xsave area which is not supported by xrstor.
+ */
+ alternative_input(
+ "1: " XRSTOR,
+ "1: " XRSTORS,
+ X86_FEATURE_XSAVES,
+ "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
+ : "memory");
+
+ asm volatile("2:\n"
+ xstate_fault
+ : "0" (0)
+ : "memory");
+
+ return err;
+}
+
+/*
+ * Save xstate context for old process during context switch.
+ */
+static inline void fpu_xsave(struct fpu *fpu)
+{
+ xsave_state(&fpu->state->xsave, -1);
+}
+
+/*
+ * Restore xstate context for new process during context switch.
+ */
+static inline int fpu_xrstor_checking(struct xsave_struct *fx)
+{
+ return xrstor_state(fx, -1);
+}
+
+/*
+ * Save xstate to user space xsave area.
+ *
+ * We don't use modified optimization because xrstor/xrstors might track
+ * a different application.
+ *
+ * We don't use compacted format xsave area for
+ * backward compatibility for old applications which don't understand
+ * compacted format of xsave area.
+ */
static inline int xsave_user(struct xsave_struct __user *buf)
{
int err;
@@ -83,69 +229,34 @@ static inline int xsave_user(struct xsave_struct __user *buf)
return -EFAULT;
__asm__ __volatile__(ASM_STAC "\n"
- "1: .byte " REX_PREFIX "0x0f,0xae,0x27\n"
+ "1:"XSAVE"\n"
"2: " ASM_CLAC "\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- _ASM_EXTABLE(1b,3b)
- : [err] "=r" (err)
+ xstate_fault
: "D" (buf), "a" (-1), "d" (-1), "0" (0)
: "memory");
return err;
}
+/*
+ * Restore xstate from user space xsave area.
+ */
static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask)
{
- int err;
+ int err = 0;
struct xsave_struct *xstate = ((__force struct xsave_struct *)buf);
u32 lmask = mask;
u32 hmask = mask >> 32;
__asm__ __volatile__(ASM_STAC "\n"
- "1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n"
+ "1:"XRSTOR"\n"
"2: " ASM_CLAC "\n"
- ".section .fixup,\"ax\"\n"
- "3: movl $-1,%[err]\n"
- " jmp 2b\n"
- ".previous\n"
- _ASM_EXTABLE(1b,3b)
- : [err] "=r" (err)
+ xstate_fault
: "D" (xstate), "a" (lmask), "d" (hmask), "0" (0)
: "memory"); /* memory required? */
return err;
}
-static inline void xrstor_state(struct xsave_struct *fx, u64 mask)
-{
- u32 lmask = mask;
- u32 hmask = mask >> 32;
-
- asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
- : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
- : "memory");
-}
-
-static inline void xsave_state(struct xsave_struct *fx, u64 mask)
-{
- u32 lmask = mask;
- u32 hmask = mask >> 32;
+void *get_xsave_addr(struct xsave_struct *xsave, int xstate);
+void setup_xstate_comp(void);
- asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x27\n\t"
- : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
- : "memory");
-}
-
-static inline void fpu_xsave(struct fpu *fpu)
-{
- /* This, however, we can work around by forcing the compiler to select
- an addressing mode that doesn't require extended registers. */
- alternative_input(
- ".byte " REX_PREFIX "0x0f,0xae,0x27",
- ".byte " REX_PREFIX "0x0f,0xae,0x37",
- X86_FEATURE_XSAVEOPT,
- [fx] "D" (&fpu->state->xsave), "a" (-1), "d" (-1) :
- "memory");
-}
#endif
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 333fd5209336..e4ab2b42bd6f 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -148,6 +148,7 @@ static int __init x86_xsave_setup(char *s)
{
setup_clear_cpu_cap(X86_FEATURE_XSAVE);
setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
+ setup_clear_cpu_cap(X86_FEATURE_XSAVES);
setup_clear_cpu_cap(X86_FEATURE_AVX);
setup_clear_cpu_cap(X86_FEATURE_AVX2);
return 1;
@@ -161,6 +162,13 @@ static int __init x86_xsaveopt_setup(char *s)
}
__setup("noxsaveopt", x86_xsaveopt_setup);
+static int __init x86_xsaves_setup(char *s)
+{
+ setup_clear_cpu_cap(X86_FEATURE_XSAVES);
+ return 1;
+}
+__setup("noxsaves", x86_xsaves_setup);
+
#ifdef CONFIG_X86_32
static int cachesize_override = -1;
static int disable_x86_serial_nr = 1;
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index d5dd80814419..a9a4229f6161 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -375,7 +375,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
/*
* These bits must be zero.
*/
- xsave_hdr->reserved1[0] = xsave_hdr->reserved1[1] = 0;
+ memset(xsave_hdr->reserved, 0, 48);
return ret;
}
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 4505e2a950d8..f804dc935d2a 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -93,6 +93,7 @@ void arch_task_cache_init(void)
kmem_cache_create("task_xstate", xstate_size,
__alignof__(union thread_xstate),
SLAB_PANIC | SLAB_NOTRACK, NULL);
+ setup_xstate_comp();
}
/*
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index a4b451c6addf..940b142cc11f 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -8,6 +8,7 @@
#include <linux/bootmem.h>
#include <linux/compat.h>
+#include <linux/cpu.h>
#include <asm/i387.h>
#include <asm/fpu-internal.h>
#include <asm/sigframe.h>
@@ -24,7 +25,9 @@ u64 pcntxt_mask;
struct xsave_struct *init_xstate_buf;
static struct _fpx_sw_bytes fx_sw_reserved, fx_sw_reserved_ia32;
-static unsigned int *xstate_offsets, *xstate_sizes, xstate_features;
+static unsigned int *xstate_offsets, *xstate_sizes;
+static unsigned int xstate_comp_offsets[sizeof(pcntxt_mask)*8];
+static unsigned int xstate_features;
/*
* If a processor implementation discern that a processor state component is
@@ -283,7 +286,7 @@ sanitize_restored_xstate(struct task_struct *tsk,
if (use_xsave()) {
/* These bits must be zero. */
- xsave_hdr->reserved1[0] = xsave_hdr->reserved1[1] = 0;
+ memset(xsave_hdr->reserved, 0, 48);
/*
* Init the state that is not present in the memory
@@ -479,6 +482,52 @@ static void __init setup_xstate_features(void)
}
/*
+ * This function sets up offsets and sizes of all extended states in
+ * xsave area. This supports both standard format and compacted format
+ * of the xsave aread.
+ *
+ * Input: void
+ * Output: void
+ */
+void setup_xstate_comp(void)
+{
+ unsigned int xstate_comp_sizes[sizeof(pcntxt_mask)*8];
+ int i;
+
+ /*
+ * The FP xstates and SSE xstates are legacy states. They are always
+ * in the fixed offsets in the xsave area in either compacted form
+ * or standard form.
+ */
+ xstate_comp_offsets[0] = 0;
+ xstate_comp_offsets[1] = offsetof(struct i387_fxsave_struct, xmm_space);
+
+ if (!cpu_has_xsaves) {
+ for (i = 2; i < xstate_features; i++) {
+ if (test_bit(i, (unsigned long *)&pcntxt_mask)) {
+ xstate_comp_offsets[i] = xstate_offsets[i];
+ xstate_comp_sizes[i] = xstate_sizes[i];
+ }
+ }
+ return;
+ }
+
+ xstate_comp_offsets[2] = FXSAVE_SIZE + XSAVE_HDR_SIZE;
+
+ for (i = 2; i < xstate_features; i++) {
+ if (test_bit(i, (unsigned long *)&pcntxt_mask))
+ xstate_comp_sizes[i] = xstate_sizes[i];
+ else
+ xstate_comp_sizes[i] = 0;
+
+ if (i > 2)
+ xstate_comp_offsets[i] = xstate_comp_offsets[i-1]
+ + xstate_comp_sizes[i-1];
+
+ }
+}
+
+/*
* setup the xstate image representing the init state
*/
static void __init setup_init_fpu_buf(void)
@@ -496,15 +545,21 @@ static void __init setup_init_fpu_buf(void)
setup_xstate_features();
+ if (cpu_has_xsaves) {
+ init_xstate_buf->xsave_hdr.xcomp_bv =
+ (u64)1 << 63 | pcntxt_mask;
+ init_xstate_buf->xsave_hdr.xstate_bv = pcntxt_mask;
+ }
+
/*
* Init all the features state with header_bv being 0x0
*/
- xrstor_state(init_xstate_buf, -1);
+ xrstor_state_booting(init_xstate_buf, -1);
/*
* Dump the init state again. This is to identify the init state
* of any feature which is not represented by all zero's.
*/
- xsave_state(init_xstate_buf, -1);
+ xsave_state_booting(init_xstate_buf, -1);
}
static enum { AUTO, ENABLE, DISABLE } eagerfpu = AUTO;
@@ -520,6 +575,30 @@ static int __init eager_fpu_setup(char *s)
}
__setup("eagerfpu=", eager_fpu_setup);
+
+/*
+ * Calculate total size of enabled xstates in XCR0/pcntxt_mask.
+ */
+static void __init init_xstate_size(void)
+{
+ unsigned int eax, ebx, ecx, edx;
+ int i;
+
+ if (!cpu_has_xsaves) {
+ cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
+ xstate_size = ebx;
+ return;
+ }
+
+ xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE;
+ for (i = 2; i < 64; i++) {
+ if (test_bit(i, (unsigned long *)&pcntxt_mask)) {
+ cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
+ xstate_size += eax;
+ }
+ }
+}
+
/*
* Enable and initialize the xsave feature.
*/
@@ -551,8 +630,7 @@ static void __init xstate_enable_boot_cpu(void)
/*
* Recompute the context size for enabled features
*/
- cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
- xstate_size = ebx;
+ init_xstate_size();
update_regset_xstate_info(xstate_size, pcntxt_mask);
prepare_fx_sw_frame();
@@ -572,8 +650,9 @@ static void __init xstate_enable_boot_cpu(void)
}
}
- pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x\n",
- pcntxt_mask, xstate_size);
+ pr_info("enabled xstate_bv 0x%llx, cntxt size 0x%x using %s\n",
+ pcntxt_mask, xstate_size,
+ cpu_has_xsaves ? "compacted form" : "standard form");
}
/*
@@ -635,3 +714,26 @@ void eager_fpu_init(void)
else
fxrstor_checking(&init_xstate_buf->i387);
}
+
+/*
+ * Given the xsave area and a state inside, this function returns the
+ * address of the state.
+ *
+ * This is the API that is called to get xstate address in either
+ * standard format or compacted format of xsave area.
+ *
+ * Inputs:
+ * xsave: base address of the xsave area;
+ * xstate: state which is defined in xsave.h (e.g. XSTATE_FP, XSTATE_SSE,
+ * etc.)
+ * Output:
+ * address of the state in the xsave area.
+ */
+void *get_xsave_addr(struct xsave_struct *xsave, int xstate)
+{
+ int feature = fls64(xstate) - 1;
+ if (!test_bit(feature, (unsigned long *)&pcntxt_mask))
+ return NULL;
+
+ return (void *)xsave + xstate_comp_offsets[feature];
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 07:13:03 +0000