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SubjectRe: AMD DC graphics display code enables -mhard-float, -msse, -msse2 without any visible FPU state protection
On Sat, 4 Apr 2020 16:32:24 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> On Sat, Apr 04, 2020 at 12:08:08PM +0900, Masami Hiramatsu wrote:
> > From c609be0b6403245612503fca1087628655bab96c Mon Sep 17 00:00:00 2001
> > From: Masami Hiramatsu <mhiramat@kernel.org>
> > Date: Fri, 3 Apr 2020 16:58:22 +0900
> > Subject: [PATCH] x86: insn: Add insn_is_fpu()
> >
> > Add insn_is_fpu(insn) which tells that the insn is
> > whether touch the MMX/XMM/YMM register or the instruction
> > of FP coprocessor.
>
> Looks good, although I changed it a little like so:

OK, and I found there is a mistake on my patch. I should not use (v) for
the instruction, which makes decoder insane.

>
> --- a/arch/x86/include/asm/insn.h
> +++ b/arch/x86/include/asm/insn.h
> @@ -133,11 +133,12 @@ static inline int insn_is_fpu(struct ins
> {
> if (!insn->opcode.got)
> insn_get_opcode(insn);
> - if (inat_is_fpu(insn->attr)) {
> + if (inat_is_fpu(insn->attr)) {
> if (insn->attr & INAT_FPUIFVEX)
> return insn_is_avx(insn);
> return 1;
> }
> + return 0;
> }
>
> static inline int insn_has_emulate_prefix(struct insn *insn)
> --- a/arch/x86/lib/x86-opcode-map.txt
> +++ b/arch/x86/lib/x86-opcode-map.txt
> @@ -269,14 +269,14 @@ d4: AAM Ib (i64)
> d5: AAD Ib (i64)
> d6:
> d7: XLAT/XLATB
> -d8: ESC
> -d9: ESC
> -da: ESC
> -db: ESC
> -dc: ESC
> -dd: ESC
> -de: ESC
> -df: ESC
> +d8: FPU
> +d9: FPU
> +da: FPU
> +db: FPU
> +dc: FPU
> +dd: FPU
> +de: FPU
> +df: FPU

I don't want to use FPU since Intel SDM is still using ESC because it
is co-processor escape code.

Here is the new patch.

From d7eca4946ab3f0d08ad1268f49418f8655aaf57c Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <mhiramat@kernel.org>
Date: Fri, 3 Apr 2020 16:58:22 +0900
Subject: [PATCH] x86: insn: Add insn_is_fpu()

Add insn_is_fpu(insn) which tells that the insn is
whether touch the MMX/XMM/YMM register or the instruction
of FP coprocessor.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
Changes:
- Fix SET* also not FPU (unless it has vex prefix.)
- Fix to remove (v) (VEX only) flag.
---
arch/x86/include/asm/inat.h | 7 +++++++
arch/x86/include/asm/insn.h | 12 ++++++++++++
arch/x86/lib/x86-opcode-map.txt | 6 +++---
arch/x86/tools/gen-insn-attr-x86.awk | 22 +++++++++++++++++-----
tools/arch/x86/include/asm/inat.h | 7 +++++++
tools/arch/x86/include/asm/insn.h | 12 ++++++++++++
tools/arch/x86/lib/x86-opcode-map.txt | 6 +++---
tools/arch/x86/tools/gen-insn-attr-x86.awk | 22 +++++++++++++++++-----
8 files changed, 78 insertions(+), 16 deletions(-)

diff --git a/arch/x86/include/asm/inat.h b/arch/x86/include/asm/inat.h
index 4cf2ad521f65..ffce45178c08 100644
--- a/arch/x86/include/asm/inat.h
+++ b/arch/x86/include/asm/inat.h
@@ -77,6 +77,8 @@
#define INAT_VEXOK (1 << (INAT_FLAG_OFFS + 5))
#define INAT_VEXONLY (1 << (INAT_FLAG_OFFS + 6))
#define INAT_EVEXONLY (1 << (INAT_FLAG_OFFS + 7))
+#define INAT_FPU (1 << (INAT_FLAG_OFFS + 8))
+#define INAT_FPUIFVEX (1 << (INAT_FLAG_OFFS + 9))
/* Attribute making macros for attribute tables */
#define INAT_MAKE_PREFIX(pfx) (pfx << INAT_PFX_OFFS)
#define INAT_MAKE_ESCAPE(esc) (esc << INAT_ESC_OFFS)
@@ -227,4 +229,9 @@ static inline int inat_must_evex(insn_attr_t attr)
{
return attr & INAT_EVEXONLY;
}
+
+static inline int inat_is_fpu(insn_attr_t attr)
+{
+ return attr & INAT_FPU;
+}
#endif
diff --git a/arch/x86/include/asm/insn.h b/arch/x86/include/asm/insn.h
index 5c1ae3eff9d4..1752c54d2103 100644
--- a/arch/x86/include/asm/insn.h
+++ b/arch/x86/include/asm/insn.h
@@ -129,6 +129,18 @@ static inline int insn_is_evex(struct insn *insn)
return (insn->vex_prefix.nbytes == 4);
}

+static inline int insn_is_fpu(struct insn *insn)
+{
+ if (!insn->opcode.got)
+ insn_get_opcode(insn);
+ if (inat_is_fpu(insn->attr)) {
+ if (insn->attr & INAT_FPUIFVEX)
+ return insn_is_avx(insn);
+ return 1;
+ }
+ return 0;
+}
+
static inline int insn_has_emulate_prefix(struct insn *insn)
{
return !!insn->emulate_prefix_size;
diff --git a/arch/x86/lib/x86-opcode-map.txt b/arch/x86/lib/x86-opcode-map.txt
index ec31f5b60323..c3d36b4c894d 100644
--- a/arch/x86/lib/x86-opcode-map.txt
+++ b/arch/x86/lib/x86-opcode-map.txt
@@ -1037,9 +1037,9 @@ EndTable

GrpTable: Grp15
0: fxsave | RDFSBASE Ry (F3),(11B)
-1: fxstor | RDGSBASE Ry (F3),(11B)
-2: vldmxcsr Md (v1) | WRFSBASE Ry (F3),(11B)
-3: vstmxcsr Md (v1) | WRGSBASE Ry (F3),(11B)
+1: fxrstor | RDGSBASE Ry (F3),(11B)
+2: ldmxcsr | vldmxcsr Md (v1) | WRFSBASE Ry (F3),(11B)
+3: stmxcsr | vstmxcsr Md (v1) | WRGSBASE Ry (F3),(11B)
4: XSAVE | ptwrite Ey (F3),(11B)
5: XRSTOR | lfence (11B) | INCSSPD/Q Ry (F3),(11B)
6: XSAVEOPT | clwb (66) | mfence (11B) | TPAUSE Rd (66),(11B) | UMONITOR Rv (F3),(11B) | UMWAIT Rd (F2),(11B) | CLRSSBSY Mq (F3)
diff --git a/arch/x86/tools/gen-insn-attr-x86.awk b/arch/x86/tools/gen-insn-attr-x86.awk
index a42015b305f4..21de6757893f 100644
--- a/arch/x86/tools/gen-insn-attr-x86.awk
+++ b/arch/x86/tools/gen-insn-attr-x86.awk
@@ -65,7 +65,11 @@ BEGIN {
modrm_expr = "^([CDEGMNPQRSUVW/][a-z]+|NTA|T[012])"
force64_expr = "\\([df]64\\)"
rex_expr = "^REX(\\.[XRWB]+)*"
- fpu_expr = "^ESC" # TODO
+
+ mmxreg_expr = "^[HLNPQUVW][a-z]+" # MMX/SSE register operands
+ mmx_expr = "^\\((emms|fxsave|fxrstor|ldmxcsr|stmxcsr)\\)" # MMX/SSE nmemonics lacking operands
+ mmxifvex_expr = "^(CMOV|SET.*)" # nmemonics NOT an AVX
+ fpu_expr = "^ESC"

lprefix1_expr = "\\((66|!F3)\\)"
lprefix2_expr = "\\(F3\\)"
@@ -236,10 +240,11 @@ function add_flags(old,new) {
}

# convert operands to flags.
-function convert_operands(count,opnd, i,j,imm,mod)
+function convert_operands(count,opnd, i,j,imm,mod,mmx)
{
imm = null
mod = null
+ mmx = null
for (j = 1; j <= count; j++) {
i = opnd[j]
if (match(i, imm_expr) == 1) {
@@ -253,7 +258,12 @@ function convert_operands(count,opnd, i,j,imm,mod)
imm = imm_flag[i]
} else if (match(i, modrm_expr))
mod = "INAT_MODRM"
+ if (match(i, mmxreg_expr) == 1) {
+ mmx = "INAT_FPU"
+ }
}
+ if (mmx)
+ imm = add_flags(imm, mmx)
return add_flags(imm, mod)
}

@@ -318,9 +328,11 @@ function convert_operands(count,opnd, i,j,imm,mod)
if (match(opcode, rex_expr))
flags = add_flags(flags, "INAT_MAKE_PREFIX(INAT_PFX_REX)")

- # check coprocessor escape : TODO
- if (match(opcode, fpu_expr))
- flags = add_flags(flags, "INAT_MODRM")
+ # check coprocessor escape
+ if (match(opcode, fpu_expr) || match(opcode, mmx_expr))
+ flags = add_flags(flags, "INAT_MODRM | INAT_FPU")
+ if (match(opcode, mmxifvex_expr))
+ flags = add_flags(flags, "INAT_FPUIFVEX")

# check VEX codes
if (match(ext, evexonly_expr))
diff --git a/tools/arch/x86/include/asm/inat.h b/tools/arch/x86/include/asm/inat.h
index 877827b7c2c3..2e6a05290efd 100644
--- a/tools/arch/x86/include/asm/inat.h
+++ b/tools/arch/x86/include/asm/inat.h
@@ -77,6 +77,8 @@
#define INAT_VEXOK (1 << (INAT_FLAG_OFFS + 5))
#define INAT_VEXONLY (1 << (INAT_FLAG_OFFS + 6))
#define INAT_EVEXONLY (1 << (INAT_FLAG_OFFS + 7))
+#define INAT_FPU (1 << (INAT_FLAG_OFFS + 8))
+#define INAT_FPUIFVEX (1 << (INAT_FLAG_OFFS + 9))
/* Attribute making macros for attribute tables */
#define INAT_MAKE_PREFIX(pfx) (pfx << INAT_PFX_OFFS)
#define INAT_MAKE_ESCAPE(esc) (esc << INAT_ESC_OFFS)
@@ -227,4 +229,9 @@ static inline int inat_must_evex(insn_attr_t attr)
{
return attr & INAT_EVEXONLY;
}
+
+static inline int inat_is_fpu(insn_attr_t attr)
+{
+ return attr & INAT_FPU;
+}
#endif
diff --git a/tools/arch/x86/include/asm/insn.h b/tools/arch/x86/include/asm/insn.h
index 568854b14d0a..d9f6bd9059c1 100644
--- a/tools/arch/x86/include/asm/insn.h
+++ b/tools/arch/x86/include/asm/insn.h
@@ -129,6 +129,18 @@ static inline int insn_is_evex(struct insn *insn)
return (insn->vex_prefix.nbytes == 4);
}

+static inline int insn_is_fpu(struct insn *insn)
+{
+ if (!insn->opcode.got)
+ insn_get_opcode(insn);
+ if (inat_is_fpu(insn->attr)) {
+ if (insn->attr & INAT_FPUIFVEX)
+ return insn_is_avx(insn);
+ return 1;
+ }
+ return 0;
+}
+
static inline int insn_has_emulate_prefix(struct insn *insn)
{
return !!insn->emulate_prefix_size;
diff --git a/tools/arch/x86/lib/x86-opcode-map.txt b/tools/arch/x86/lib/x86-opcode-map.txt
index ec31f5b60323..c3d36b4c894d 100644
--- a/tools/arch/x86/lib/x86-opcode-map.txt
+++ b/tools/arch/x86/lib/x86-opcode-map.txt
@@ -1037,9 +1037,9 @@ EndTable

GrpTable: Grp15
0: fxsave | RDFSBASE Ry (F3),(11B)
-1: fxstor | RDGSBASE Ry (F3),(11B)
-2: vldmxcsr Md (v1) | WRFSBASE Ry (F3),(11B)
-3: vstmxcsr Md (v1) | WRGSBASE Ry (F3),(11B)
+1: fxrstor | RDGSBASE Ry (F3),(11B)
+2: ldmxcsr | vldmxcsr Md (v1) | WRFSBASE Ry (F3),(11B)
+3: stmxcsr | vstmxcsr Md (v1) | WRGSBASE Ry (F3),(11B)
4: XSAVE | ptwrite Ey (F3),(11B)
5: XRSTOR | lfence (11B) | INCSSPD/Q Ry (F3),(11B)
6: XSAVEOPT | clwb (66) | mfence (11B) | TPAUSE Rd (66),(11B) | UMONITOR Rv (F3),(11B) | UMWAIT Rd (F2),(11B) | CLRSSBSY Mq (F3)
diff --git a/tools/arch/x86/tools/gen-insn-attr-x86.awk b/tools/arch/x86/tools/gen-insn-attr-x86.awk
index a42015b305f4..21de6757893f 100644
--- a/tools/arch/x86/tools/gen-insn-attr-x86.awk
+++ b/tools/arch/x86/tools/gen-insn-attr-x86.awk
@@ -65,7 +65,11 @@ BEGIN {
modrm_expr = "^([CDEGMNPQRSUVW/][a-z]+|NTA|T[012])"
force64_expr = "\\([df]64\\)"
rex_expr = "^REX(\\.[XRWB]+)*"
- fpu_expr = "^ESC" # TODO
+
+ mmxreg_expr = "^[HLNPQUVW][a-z]+" # MMX/SSE register operands
+ mmx_expr = "^\\((emms|fxsave|fxrstor|ldmxcsr|stmxcsr)\\)" # MMX/SSE nmemonics lacking operands
+ mmxifvex_expr = "^(CMOV|SET.*)" # nmemonics NOT an AVX
+ fpu_expr = "^ESC"

lprefix1_expr = "\\((66|!F3)\\)"
lprefix2_expr = "\\(F3\\)"
@@ -236,10 +240,11 @@ function add_flags(old,new) {
}

# convert operands to flags.
-function convert_operands(count,opnd, i,j,imm,mod)
+function convert_operands(count,opnd, i,j,imm,mod,mmx)
{
imm = null
mod = null
+ mmx = null
for (j = 1; j <= count; j++) {
i = opnd[j]
if (match(i, imm_expr) == 1) {
@@ -253,7 +258,12 @@ function convert_operands(count,opnd, i,j,imm,mod)
imm = imm_flag[i]
} else if (match(i, modrm_expr))
mod = "INAT_MODRM"
+ if (match(i, mmxreg_expr) == 1) {
+ mmx = "INAT_FPU"
+ }
}
+ if (mmx)
+ imm = add_flags(imm, mmx)
return add_flags(imm, mod)
}

@@ -318,9 +328,11 @@ function convert_operands(count,opnd, i,j,imm,mod)
if (match(opcode, rex_expr))
flags = add_flags(flags, "INAT_MAKE_PREFIX(INAT_PFX_REX)")

- # check coprocessor escape : TODO
- if (match(opcode, fpu_expr))
- flags = add_flags(flags, "INAT_MODRM")
+ # check coprocessor escape
+ if (match(opcode, fpu_expr) || match(opcode, mmx_expr))
+ flags = add_flags(flags, "INAT_MODRM | INAT_FPU")
+ if (match(opcode, mmxifvex_expr))
+ flags = add_flags(flags, "INAT_FPUIFVEX")

# check VEX codes
if (match(ext, evexonly_expr))
--
2.20.1

Thank you,

--
Masami Hiramatsu <mhiramat@kernel.org>

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