6.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Adrian Hunter adrian.hunter@intel.com
[ Upstream commit 59162e0c11d7257cde15f907d19fefe26da66692 ]
The x86 instruction decoder is used not only for decoding kernel instructions. It is also used by perf uprobes (user space probes) and by perf tools Intel Processor Trace decoding. Consequently, it needs to support instructions executed by user space also.
Opcode 0x68 PUSH instruction is currently defined as 64-bit operand size only i.e. (d64). That was based on Intel SDM Opcode Map. However that is contradicted by the Instruction Set Reference section for PUSH in the same manual.
Remove 64-bit operand size only annotation from opcode 0x68 PUSH instruction.
Example:
$ cat pushw.s .global _start .text _start: pushw $0x1234 mov $0x1,%eax # system call number (sys_exit) int $0x80 $ as -o pushw.o pushw.s $ ld -s -o pushw pushw.o $ objdump -d pushw | tail -4 0000000000401000 <.text>: 401000: 66 68 34 12 pushw $0x1234 401004: b8 01 00 00 00 mov $0x1,%eax 401009: cd 80 int $0x80 $ perf record -e intel_pt//u ./pushw [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.014 MB perf.data ]
Before:
$ perf script --insn-trace=disasm Warning: 1 instruction trace errors pushw 10349 [000] 10586.869237014: 401000 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw) pushw $0x1234 pushw 10349 [000] 10586.869237014: 401006 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw) addb %al, (%rax) pushw 10349 [000] 10586.869237014: 401008 [unknown] (/home/ahunter/git/misc/rtit-tests/pushw) addb %cl, %ch pushw 10349 [000] 10586.869237014: 40100a [unknown] (/home/ahunter/git/misc/rtit-tests/pushw) addb $0x2e, (%rax) instruction trace error type 1 time 10586.869237224 cpu 0 pid 10349 tid 10349 ip 0x40100d code 6: Trace doesn't match instruction
After:
$ perf script --insn-trace=disasm pushw 10349 [000] 10586.869237014: 401000 [unknown] (./pushw) pushw $0x1234 pushw 10349 [000] 10586.869237014: 401004 [unknown] (./pushw) movl $1, %eax
Fixes: eb13296cfaf6 ("x86: Instruction decoder API") Signed-off-by: Adrian Hunter adrian.hunter@intel.com Signed-off-by: Ingo Molnar mingo@kernel.org Link: https://lore.kernel.org/r/20240502105853.5338-3-adrian.hunter@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/lib/x86-opcode-map.txt | 2 +- tools/arch/x86/lib/x86-opcode-map.txt | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/lib/x86-opcode-map.txt b/arch/x86/lib/x86-opcode-map.txt index 5168ee0360b24..940913550ed83 100644 --- a/arch/x86/lib/x86-opcode-map.txt +++ b/arch/x86/lib/x86-opcode-map.txt @@ -148,7 +148,7 @@ AVXcode: 65: SEG=GS (Prefix) 66: Operand-Size (Prefix) 67: Address-Size (Prefix) -68: PUSH Iz (d64) +68: PUSH Iz 69: IMUL Gv,Ev,Iz 6a: PUSH Ib (d64) 6b: IMUL Gv,Ev,Ib diff --git a/tools/arch/x86/lib/x86-opcode-map.txt b/tools/arch/x86/lib/x86-opcode-map.txt index 5168ee0360b24..940913550ed83 100644 --- a/tools/arch/x86/lib/x86-opcode-map.txt +++ b/tools/arch/x86/lib/x86-opcode-map.txt @@ -148,7 +148,7 @@ AVXcode: 65: SEG=GS (Prefix) 66: Operand-Size (Prefix) 67: Address-Size (Prefix) -68: PUSH Iz (d64) +68: PUSH Iz 69: IMUL Gv,Ev,Iz 6a: PUSH Ib (d64) 6b: IMUL Gv,Ev,Ib