* [PATCH 5.15 v2 1/3] x86/alternatives: Introduce int3_emulate_jcc()
2024-03-18 13:39 [PATCH 5.15 v2 0/3] Support static calls with LLVM-built kernels Thadeu Lima de Souza Cascardo
@ 2024-03-18 13:39 ` Thadeu Lima de Souza Cascardo
2024-03-18 13:39 ` [PATCH 5.15 v2 2/3] x86/alternatives: Teach text_poke_bp() to patch Jcc.d32 instructions Thadeu Lima de Souza Cascardo
` (2 subsequent siblings)
3 siblings, 0 replies; 8+ messages in thread
From: Thadeu Lima de Souza Cascardo @ 2024-03-18 13:39 UTC (permalink / raw)
To: stable; +Cc: Peter Zijlstra, Thomas Gleixner, Ingo Molnar, kernel-dev
From: Peter Zijlstra <peterz@infradead.org>
commit db7adcfd1cec4e95155e37bc066fddab302c6340 upstream.
Move the kprobe Jcc emulation into int3_emulate_jcc() so it can be
used by more code -- specifically static_call() will need this.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20230123210607.057678245@infradead.org
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
---
arch/x86/include/asm/text-patching.h | 31 +++++++++++++++++++++++
arch/x86/kernel/kprobes/core.c | 38 ++++++----------------------
2 files changed, 39 insertions(+), 30 deletions(-)
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index c6015b407461..7281ce64e99d 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -181,6 +181,37 @@ void int3_emulate_ret(struct pt_regs *regs)
unsigned long ip = int3_emulate_pop(regs);
int3_emulate_jmp(regs, ip);
}
+
+static __always_inline
+void int3_emulate_jcc(struct pt_regs *regs, u8 cc, unsigned long ip, unsigned long disp)
+{
+ static const unsigned long jcc_mask[6] = {
+ [0] = X86_EFLAGS_OF,
+ [1] = X86_EFLAGS_CF,
+ [2] = X86_EFLAGS_ZF,
+ [3] = X86_EFLAGS_CF | X86_EFLAGS_ZF,
+ [4] = X86_EFLAGS_SF,
+ [5] = X86_EFLAGS_PF,
+ };
+
+ bool invert = cc & 1;
+ bool match;
+
+ if (cc < 0xc) {
+ match = regs->flags & jcc_mask[cc >> 1];
+ } else {
+ match = ((regs->flags & X86_EFLAGS_SF) >> X86_EFLAGS_SF_BIT) ^
+ ((regs->flags & X86_EFLAGS_OF) >> X86_EFLAGS_OF_BIT);
+ if (cc >= 0xe)
+ match = match || (regs->flags & X86_EFLAGS_ZF);
+ }
+
+ if ((match && !invert) || (!match && invert))
+ ip += disp;
+
+ int3_emulate_jmp(regs, ip);
+}
+
#endif /* !CONFIG_UML_X86 */
#endif /* _ASM_X86_TEXT_PATCHING_H */
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 052ea7425c4d..893f040b97b7 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -463,50 +463,26 @@ static void kprobe_emulate_call(struct kprobe *p, struct pt_regs *regs)
}
NOKPROBE_SYMBOL(kprobe_emulate_call);
-static nokprobe_inline
-void __kprobe_emulate_jmp(struct kprobe *p, struct pt_regs *regs, bool cond)
+static void kprobe_emulate_jmp(struct kprobe *p, struct pt_regs *regs)
{
unsigned long ip = regs->ip - INT3_INSN_SIZE + p->ainsn.size;
- if (cond)
- ip += p->ainsn.rel32;
+ ip += p->ainsn.rel32;
int3_emulate_jmp(regs, ip);
}
-
-static void kprobe_emulate_jmp(struct kprobe *p, struct pt_regs *regs)
-{
- __kprobe_emulate_jmp(p, regs, true);
-}
NOKPROBE_SYMBOL(kprobe_emulate_jmp);
-static const unsigned long jcc_mask[6] = {
- [0] = X86_EFLAGS_OF,
- [1] = X86_EFLAGS_CF,
- [2] = X86_EFLAGS_ZF,
- [3] = X86_EFLAGS_CF | X86_EFLAGS_ZF,
- [4] = X86_EFLAGS_SF,
- [5] = X86_EFLAGS_PF,
-};
-
static void kprobe_emulate_jcc(struct kprobe *p, struct pt_regs *regs)
{
- bool invert = p->ainsn.jcc.type & 1;
- bool match;
+ unsigned long ip = regs->ip - INT3_INSN_SIZE + p->ainsn.size;
- if (p->ainsn.jcc.type < 0xc) {
- match = regs->flags & jcc_mask[p->ainsn.jcc.type >> 1];
- } else {
- match = ((regs->flags & X86_EFLAGS_SF) >> X86_EFLAGS_SF_BIT) ^
- ((regs->flags & X86_EFLAGS_OF) >> X86_EFLAGS_OF_BIT);
- if (p->ainsn.jcc.type >= 0xe)
- match = match || (regs->flags & X86_EFLAGS_ZF);
- }
- __kprobe_emulate_jmp(p, regs, (match && !invert) || (!match && invert));
+ int3_emulate_jcc(regs, p->ainsn.jcc.type, ip, p->ainsn.rel32);
}
NOKPROBE_SYMBOL(kprobe_emulate_jcc);
static void kprobe_emulate_loop(struct kprobe *p, struct pt_regs *regs)
{
+ unsigned long ip = regs->ip - INT3_INSN_SIZE + p->ainsn.size;
bool match;
if (p->ainsn.loop.type != 3) { /* LOOP* */
@@ -534,7 +510,9 @@ static void kprobe_emulate_loop(struct kprobe *p, struct pt_regs *regs)
else if (p->ainsn.loop.type == 1) /* LOOPE */
match = match && (regs->flags & X86_EFLAGS_ZF);
- __kprobe_emulate_jmp(p, regs, match);
+ if (match)
+ ip += p->ainsn.rel32;
+ int3_emulate_jmp(regs, ip);
}
NOKPROBE_SYMBOL(kprobe_emulate_loop);
--
2.34.1
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH 5.15 v2 2/3] x86/alternatives: Teach text_poke_bp() to patch Jcc.d32 instructions
2024-03-18 13:39 [PATCH 5.15 v2 0/3] Support static calls with LLVM-built kernels Thadeu Lima de Souza Cascardo
2024-03-18 13:39 ` [PATCH 5.15 v2 1/3] x86/alternatives: Introduce int3_emulate_jcc() Thadeu Lima de Souza Cascardo
@ 2024-03-18 13:39 ` Thadeu Lima de Souza Cascardo
2024-03-18 13:39 ` [PATCH 5.15 v2 3/3] x86/static_call: Add support for Jcc tail-calls Thadeu Lima de Souza Cascardo
2024-03-29 12:50 ` [PATCH 5.15 v2 0/3] Support static calls with LLVM-built kernels Greg KH
3 siblings, 0 replies; 8+ messages in thread
From: Thadeu Lima de Souza Cascardo @ 2024-03-18 13:39 UTC (permalink / raw)
To: stable; +Cc: Peter Zijlstra, Thomas Gleixner, Ingo Molnar, kernel-dev
From: Peter Zijlstra <peterz@infradead.org>
commit ac0ee0a9560c97fa5fe1409e450c2425d4ebd17a upstream.
In order to re-write Jcc.d32 instructions text_poke_bp() needs to be
taught about them.
The biggest hurdle is that the whole machinery is currently made for 5
byte instructions and extending this would grow struct text_poke_loc
which is currently a nice 16 bytes and used in an array.
However, since text_poke_loc contains a full copy of the (s32)
displacement, it is possible to map the Jcc.d32 2 byte opcodes to
Jcc.d8 1 byte opcode for the int3 emulation.
This then leaves the replacement bytes; fudge that by only storing the
last 5 bytes and adding the rule that 'length == 6' instruction will
be prefixed with a 0x0f byte.
Change-Id: Ie3f72c6b92f865d287c8940e5a87e59d41cfaa27
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20230123210607.115718513@infradead.org
[cascardo: there is no emit_call_track_retpoline]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
---
arch/x86/kernel/alternative.c | 56 +++++++++++++++++++++++++++++------
1 file changed, 47 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index e5536edbae57..5614e6d219b7 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -351,6 +351,12 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
kasan_enable_current();
}
+static inline bool is_jcc32(struct insn *insn)
+{
+ /* Jcc.d32 second opcode byte is in the range: 0x80-0x8f */
+ return insn->opcode.bytes[0] == 0x0f && (insn->opcode.bytes[1] & 0xf0) == 0x80;
+}
+
#if defined(CONFIG_RETPOLINE) && defined(CONFIG_STACK_VALIDATION)
/*
@@ -1201,6 +1207,11 @@ void text_poke_sync(void)
on_each_cpu(do_sync_core, NULL, 1);
}
+/*
+ * NOTE: crazy scheme to allow patching Jcc.d32 but not increase the size of
+ * this thing. When len == 6 everything is prefixed with 0x0f and we map
+ * opcode to Jcc.d8, using len to distinguish.
+ */
struct text_poke_loc {
/* addr := _stext + rel_addr */
s32 rel_addr;
@@ -1322,6 +1333,10 @@ noinstr int poke_int3_handler(struct pt_regs *regs)
int3_emulate_jmp(regs, (long)ip + tp->disp);
break;
+ case 0x70 ... 0x7f: /* Jcc */
+ int3_emulate_jcc(regs, tp->opcode & 0xf, (long)ip, tp->disp);
+ break;
+
default:
BUG();
}
@@ -1395,16 +1410,26 @@ static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries
* Second step: update all but the first byte of the patched range.
*/
for (do_sync = 0, i = 0; i < nr_entries; i++) {
- u8 old[POKE_MAX_OPCODE_SIZE] = { tp[i].old, };
+ u8 old[POKE_MAX_OPCODE_SIZE+1] = { tp[i].old, };
+ u8 _new[POKE_MAX_OPCODE_SIZE+1];
+ const u8 *new = tp[i].text;
int len = tp[i].len;
if (len - INT3_INSN_SIZE > 0) {
memcpy(old + INT3_INSN_SIZE,
text_poke_addr(&tp[i]) + INT3_INSN_SIZE,
len - INT3_INSN_SIZE);
+
+ if (len == 6) {
+ _new[0] = 0x0f;
+ memcpy(_new + 1, new, 5);
+ new = _new;
+ }
+
text_poke(text_poke_addr(&tp[i]) + INT3_INSN_SIZE,
- (const char *)tp[i].text + INT3_INSN_SIZE,
+ new + INT3_INSN_SIZE,
len - INT3_INSN_SIZE);
+
do_sync++;
}
@@ -1432,8 +1457,7 @@ static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries
* The old instruction is recorded so that the event can be
* processed forwards or backwards.
*/
- perf_event_text_poke(text_poke_addr(&tp[i]), old, len,
- tp[i].text, len);
+ perf_event_text_poke(text_poke_addr(&tp[i]), old, len, new, len);
}
if (do_sync) {
@@ -1450,10 +1474,15 @@ static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries
* replacing opcode.
*/
for (do_sync = 0, i = 0; i < nr_entries; i++) {
- if (tp[i].text[0] == INT3_INSN_OPCODE)
+ u8 byte = tp[i].text[0];
+
+ if (tp[i].len == 6)
+ byte = 0x0f;
+
+ if (byte == INT3_INSN_OPCODE)
continue;
- text_poke(text_poke_addr(&tp[i]), tp[i].text, INT3_INSN_SIZE);
+ text_poke(text_poke_addr(&tp[i]), &byte, INT3_INSN_SIZE);
do_sync++;
}
@@ -1471,9 +1500,11 @@ static void text_poke_loc_init(struct text_poke_loc *tp, void *addr,
const void *opcode, size_t len, const void *emulate)
{
struct insn insn;
- int ret, i;
+ int ret, i = 0;
- memcpy((void *)tp->text, opcode, len);
+ if (len == 6)
+ i = 1;
+ memcpy((void *)tp->text, opcode+i, len-i);
if (!emulate)
emulate = opcode;
@@ -1484,6 +1515,13 @@ static void text_poke_loc_init(struct text_poke_loc *tp, void *addr,
tp->len = len;
tp->opcode = insn.opcode.bytes[0];
+ if (is_jcc32(&insn)) {
+ /*
+ * Map Jcc.d32 onto Jcc.d8 and use len to distinguish.
+ */
+ tp->opcode = insn.opcode.bytes[1] - 0x10;
+ }
+
switch (tp->opcode) {
case RET_INSN_OPCODE:
case JMP32_INSN_OPCODE:
@@ -1500,7 +1538,6 @@ static void text_poke_loc_init(struct text_poke_loc *tp, void *addr,
BUG_ON(len != insn.length);
};
-
switch (tp->opcode) {
case INT3_INSN_OPCODE:
case RET_INSN_OPCODE:
@@ -1509,6 +1546,7 @@ static void text_poke_loc_init(struct text_poke_loc *tp, void *addr,
case CALL_INSN_OPCODE:
case JMP32_INSN_OPCODE:
case JMP8_INSN_OPCODE:
+ case 0x70 ... 0x7f: /* Jcc */
tp->disp = insn.immediate.value;
break;
--
2.34.1
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH 5.15 v2 3/3] x86/static_call: Add support for Jcc tail-calls
2024-03-18 13:39 [PATCH 5.15 v2 0/3] Support static calls with LLVM-built kernels Thadeu Lima de Souza Cascardo
2024-03-18 13:39 ` [PATCH 5.15 v2 1/3] x86/alternatives: Introduce int3_emulate_jcc() Thadeu Lima de Souza Cascardo
2024-03-18 13:39 ` [PATCH 5.15 v2 2/3] x86/alternatives: Teach text_poke_bp() to patch Jcc.d32 instructions Thadeu Lima de Souza Cascardo
@ 2024-03-18 13:39 ` Thadeu Lima de Souza Cascardo
2024-03-29 12:50 ` [PATCH 5.15 v2 0/3] Support static calls with LLVM-built kernels Greg KH
3 siblings, 0 replies; 8+ messages in thread
From: Thadeu Lima de Souza Cascardo @ 2024-03-18 13:39 UTC (permalink / raw)
To: stable; +Cc: Peter Zijlstra, Thomas Gleixner, Ingo Molnar, kernel-dev
From: Peter Zijlstra <peterz@infradead.org>
commit 923510c88d2b7d947c4217835fd9ca6bd65cc56c upstream.
Clang likes to create conditional tail calls like:
0000000000000350 <amd_pmu_add_event>:
350: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 351: R_X86_64_NONE __fentry__-0x4
355: 48 83 bf 20 01 00 00 00 cmpq $0x0,0x120(%rdi)
35d: 0f 85 00 00 00 00 jne 363 <amd_pmu_add_event+0x13> 35f: R_X86_64_PLT32 __SCT__amd_pmu_branch_add-0x4
363: e9 00 00 00 00 jmp 368 <amd_pmu_add_event+0x18> 364: R_X86_64_PLT32 __x86_return_thunk-0x4
Where 0x35d is a static call site that's turned into a conditional
tail-call using the Jcc class of instructions.
Teach the in-line static call text patching about this.
Notably, since there is no conditional-ret, in that case patch the Jcc
to point at an empty stub function that does the ret -- or the return
thunk when needed.
Reported-by: "Erhard F." <erhard_f@mailbox.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/Y9Kdg9QjHkr9G5b5@hirez.programming.kicks-ass.net
[nathan: Backport to 6.1:
- Use __x86_return_thunk instead of x86_return_thunk for func in
__static_call_transform()
- Remove ASM_FUNC_ALIGN in __static_call_return() asm, as call
depth tracking was merged in 6.2]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[cascardo: __static_call_validate didn't have the bool tramp argument]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
---
arch/x86/kernel/static_call.c | 49 ++++++++++++++++++++++++++++++++---
1 file changed, 46 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/static_call.c b/arch/x86/kernel/static_call.c
index e25050c7ff1e..94378f202c50 100644
--- a/arch/x86/kernel/static_call.c
+++ b/arch/x86/kernel/static_call.c
@@ -9,6 +9,7 @@ enum insn_type {
NOP = 1, /* site cond-call */
JMP = 2, /* tramp / site tail-call */
RET = 3, /* tramp / site cond-tail-call */
+ JCC = 4,
};
/*
@@ -25,12 +26,39 @@ static const u8 xor5rax[] = { 0x2e, 0x2e, 0x2e, 0x31, 0xc0 };
static const u8 retinsn[] = { RET_INSN_OPCODE, 0xcc, 0xcc, 0xcc, 0xcc };
+static u8 __is_Jcc(u8 *insn) /* Jcc.d32 */
+{
+ u8 ret = 0;
+
+ if (insn[0] == 0x0f) {
+ u8 tmp = insn[1];
+ if ((tmp & 0xf0) == 0x80)
+ ret = tmp;
+ }
+
+ return ret;
+}
+
+extern void __static_call_return(void);
+
+asm (".global __static_call_return\n\t"
+ ".type __static_call_return, @function\n\t"
+ "__static_call_return:\n\t"
+ ANNOTATE_NOENDBR
+ ANNOTATE_RETPOLINE_SAFE
+ "ret; int3\n\t"
+ ".size __static_call_return, . - __static_call_return \n\t");
+
static void __ref __static_call_transform(void *insn, enum insn_type type,
void *func, bool modinit)
{
const void *emulate = NULL;
int size = CALL_INSN_SIZE;
const void *code;
+ u8 op, buf[6];
+
+ if ((type == JMP || type == RET) && (op = __is_Jcc(insn)))
+ type = JCC;
switch (type) {
case CALL:
@@ -56,6 +84,20 @@ static void __ref __static_call_transform(void *insn, enum insn_type type,
else
code = &retinsn;
break;
+
+ case JCC:
+ if (!func) {
+ func = __static_call_return;
+ if (cpu_feature_enabled(X86_FEATURE_RETHUNK))
+ func = __x86_return_thunk;
+ }
+
+ buf[0] = 0x0f;
+ __text_gen_insn(buf+1, op, insn+1, func, 5);
+ code = buf;
+ size = 6;
+
+ break;
}
if (memcmp(insn, code, size) == 0)
@@ -67,13 +109,14 @@ static void __ref __static_call_transform(void *insn, enum insn_type type,
text_poke_bp(insn, code, size, emulate);
}
-static void __static_call_validate(void *insn, bool tail)
+static void __static_call_validate(u8 *insn, bool tail)
{
- u8 opcode = *(u8 *)insn;
+ u8 opcode = insn[0];
if (tail) {
if (opcode == JMP32_INSN_OPCODE ||
- opcode == RET_INSN_OPCODE)
+ opcode == RET_INSN_OPCODE ||
+ __is_Jcc(insn))
return;
} else {
if (opcode == CALL_INSN_OPCODE ||
--
2.34.1
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH 5.15 v2 0/3] Support static calls with LLVM-built kernels
2024-03-18 13:39 [PATCH 5.15 v2 0/3] Support static calls with LLVM-built kernels Thadeu Lima de Souza Cascardo
` (2 preceding siblings ...)
2024-03-18 13:39 ` [PATCH 5.15 v2 3/3] x86/static_call: Add support for Jcc tail-calls Thadeu Lima de Souza Cascardo
@ 2024-03-29 12:50 ` Greg KH
2024-03-30 9:57 ` Thadeu Lima de Souza Cascardo
3 siblings, 1 reply; 8+ messages in thread
From: Greg KH @ 2024-03-29 12:50 UTC (permalink / raw)
To: Thadeu Lima de Souza Cascardo
Cc: stable, Peter Zijlstra, Thomas Gleixner, Ingo Molnar, kernel-dev
On Mon, Mar 18, 2024 at 10:39:04AM -0300, Thadeu Lima de Souza Cascardo wrote:
> Otherwise, we see warnings like this:
>
> [ 0.000000][ T0] ------------[ cut here ]------------
> [ 0.000000][ T0] unexpected static_call insn opcode 0xf at kvm_vcpu_reload_apic_access_page+0x17/0x30
> [ 0.000000][ T0] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/static_call.c:88 __static_call_validate+0x68/0x70
> [ 0.000000][ T0] Modules linked in:
> [ 0.000000][ T0] CPU: 0 PID: 0 Comm: swapper Not tainted 5.15.151-00083-gf200c7260296 #68 fe3cb25cf78cb710722bb5acd1cadddd35172924
> [ 0.000000][ T0] RIP: 0010:__static_call_validate+0x68/0x70
> [ 0.000000][ T0] Code: 0f b6 4a 04 81 f1 c0 00 00 00 09 c1 74 cc 80 3d be 2c 02 02 00 75 c3 c6 05 b5 2c 02 02 01 48 c7 c7 38 4f c3 82 e8 e8 c8 09 00 <0f> 0b c3 00 00 cc cc 00 53 48 89 fb 48 63 15 31 71 06 02
> e8 b0 b8
> [ 0.000000][ T0] RSP: 0000:ffffffff82e03e70 EFLAGS: 00010046 ORIG_RAX: 0000000000000000
> [ 0.000000][ T0] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
> [ 0.000000][ T0] RDX: 0000000000000000 RSI: ffffffff82e03ce0 RDI: 0000000000000001
> [ 0.000000][ T0] RBP: 0000000000000001 R08: 00000000ffffffff R09: ffffffff82eaab70
> [ 0.000000][ T0] R10: ffffffff82e2e900 R11: 205d305420202020 R12: ffffffff82e51960
> [ 0.000000][ T0] R13: ffffffff81038987 R14: ffffffff81038987 R15: 0000000000000001
> [ 0.000000][ T0] FS: 0000000000000000(0000) GS:ffffffff83726000(0000) knlGS:0000000000000000
> [ 0.000000][ T0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 0.000000][ T0] CR2: ffff888000014be8 CR3: 00000000037b2000 CR4: 00000000000000a0
> [ 0.000000][ T0] Call Trace:
> [ 0.000000][ T0] <TASK>
> [ 0.000000][ T0] ? __warn+0x75/0xe0
> [ 0.000000][ T0] ? report_bug+0x81/0xe0
> [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> [ 0.000000][ T0] ? early_fixup_exception+0x44/0xa0
> [ 0.000000][ T0] ? early_idt_handler_common+0x2f/0x40
> [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> [ 0.000000][ T0] ? __static_call_validate+0x68/0x70
> [ 0.000000][ T0] ? arch_static_call_transform+0x5c/0x90
> [ 0.000000][ T0] ? __static_call_init+0x1ec/0x230
> [ 0.000000][ T0] ? static_call_init+0x32/0x70
> [ 0.000000][ T0] ? setup_arch+0x36/0x4f0
> [ 0.000000][ T0] ? start_kernel+0x67/0x400
> [ 0.000000][ T0] ? secondary_startup_64_no_verify+0xb1/0xbb
> [ 0.000000][ T0] </TASK>
> [ 0.000000][ T0] ---[ end trace 8c8589c01f370686 ]---
>
>
>
> Peter Zijlstra (3):
> x86/alternatives: Introduce int3_emulate_jcc()
> x86/alternatives: Teach text_poke_bp() to patch Jcc.d32 instructions
> x86/static_call: Add support for Jcc tail-calls
>
> arch/x86/include/asm/text-patching.h | 31 +++++++++++++++
> arch/x86/kernel/alternative.c | 56 +++++++++++++++++++++++-----
> arch/x86/kernel/kprobes/core.c | 38 ++++---------------
> arch/x86/kernel/static_call.c | 49 ++++++++++++++++++++++--
> 4 files changed, 132 insertions(+), 42 deletions(-)
Why is there a v2 series here? Are the ones I just took not correct?
confused,
greg k-h
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH 5.15 v2 0/3] Support static calls with LLVM-built kernels
2024-03-29 12:50 ` [PATCH 5.15 v2 0/3] Support static calls with LLVM-built kernels Greg KH
@ 2024-03-30 9:57 ` Thadeu Lima de Souza Cascardo
2024-03-30 10:11 ` Greg KH
0 siblings, 1 reply; 8+ messages in thread
From: Thadeu Lima de Souza Cascardo @ 2024-03-30 9:57 UTC (permalink / raw)
To: Greg KH; +Cc: stable, Peter Zijlstra, Thomas Gleixner, Ingo Molnar, kernel-dev
On Fri, Mar 29, 2024 at 01:50:11PM +0100, Greg KH wrote:
> On Mon, Mar 18, 2024 at 10:39:04AM -0300, Thadeu Lima de Souza Cascardo wrote:
> > Otherwise, we see warnings like this:
> >
> > [ 0.000000][ T0] ------------[ cut here ]------------
> > [ 0.000000][ T0] unexpected static_call insn opcode 0xf at kvm_vcpu_reload_apic_access_page+0x17/0x30
> > [ 0.000000][ T0] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/static_call.c:88 __static_call_validate+0x68/0x70
> > [ 0.000000][ T0] Modules linked in:
> > [ 0.000000][ T0] CPU: 0 PID: 0 Comm: swapper Not tainted 5.15.151-00083-gf200c7260296 #68 fe3cb25cf78cb710722bb5acd1cadddd35172924
> > [ 0.000000][ T0] RIP: 0010:__static_call_validate+0x68/0x70
> > [ 0.000000][ T0] Code: 0f b6 4a 04 81 f1 c0 00 00 00 09 c1 74 cc 80 3d be 2c 02 02 00 75 c3 c6 05 b5 2c 02 02 01 48 c7 c7 38 4f c3 82 e8 e8 c8 09 00 <0f> 0b c3 00 00 cc cc 00 53 48 89 fb 48 63 15 31 71 06 02
> > e8 b0 b8
> > [ 0.000000][ T0] RSP: 0000:ffffffff82e03e70 EFLAGS: 00010046 ORIG_RAX: 0000000000000000
> > [ 0.000000][ T0] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
> > [ 0.000000][ T0] RDX: 0000000000000000 RSI: ffffffff82e03ce0 RDI: 0000000000000001
> > [ 0.000000][ T0] RBP: 0000000000000001 R08: 00000000ffffffff R09: ffffffff82eaab70
> > [ 0.000000][ T0] R10: ffffffff82e2e900 R11: 205d305420202020 R12: ffffffff82e51960
> > [ 0.000000][ T0] R13: ffffffff81038987 R14: ffffffff81038987 R15: 0000000000000001
> > [ 0.000000][ T0] FS: 0000000000000000(0000) GS:ffffffff83726000(0000) knlGS:0000000000000000
> > [ 0.000000][ T0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 0.000000][ T0] CR2: ffff888000014be8 CR3: 00000000037b2000 CR4: 00000000000000a0
> > [ 0.000000][ T0] Call Trace:
> > [ 0.000000][ T0] <TASK>
> > [ 0.000000][ T0] ? __warn+0x75/0xe0
> > [ 0.000000][ T0] ? report_bug+0x81/0xe0
> > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > [ 0.000000][ T0] ? early_fixup_exception+0x44/0xa0
> > [ 0.000000][ T0] ? early_idt_handler_common+0x2f/0x40
> > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > [ 0.000000][ T0] ? __static_call_validate+0x68/0x70
> > [ 0.000000][ T0] ? arch_static_call_transform+0x5c/0x90
> > [ 0.000000][ T0] ? __static_call_init+0x1ec/0x230
> > [ 0.000000][ T0] ? static_call_init+0x32/0x70
> > [ 0.000000][ T0] ? setup_arch+0x36/0x4f0
> > [ 0.000000][ T0] ? start_kernel+0x67/0x400
> > [ 0.000000][ T0] ? secondary_startup_64_no_verify+0xb1/0xbb
> > [ 0.000000][ T0] </TASK>
> > [ 0.000000][ T0] ---[ end trace 8c8589c01f370686 ]---
> >
> >
> >
> > Peter Zijlstra (3):
> > x86/alternatives: Introduce int3_emulate_jcc()
> > x86/alternatives: Teach text_poke_bp() to patch Jcc.d32 instructions
> > x86/static_call: Add support for Jcc tail-calls
> >
> > arch/x86/include/asm/text-patching.h | 31 +++++++++++++++
> > arch/x86/kernel/alternative.c | 56 +++++++++++++++++++++++-----
> > arch/x86/kernel/kprobes/core.c | 38 ++++---------------
> > arch/x86/kernel/static_call.c | 49 ++++++++++++++++++++++--
> > 4 files changed, 132 insertions(+), 42 deletions(-)
>
> Why is there a v2 series here? Are the ones I just took not correct?
>
> confused,
>
> greg k-h
Because Sasha questioned the presence of the first 2 patches in the series
while they were not backported to 6.1. Then, I looked at the 6.1 backport for
reference and determined they were not really necessary if I picked the same
changes that the 6.1 backport applied.
Thanks.
Cascardo.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 5.15 v2 0/3] Support static calls with LLVM-built kernels
2024-03-30 9:57 ` Thadeu Lima de Souza Cascardo
@ 2024-03-30 10:11 ` Greg KH
2024-03-30 18:10 ` Thadeu Lima de Souza Cascardo
0 siblings, 1 reply; 8+ messages in thread
From: Greg KH @ 2024-03-30 10:11 UTC (permalink / raw)
To: Thadeu Lima de Souza Cascardo
Cc: stable, Peter Zijlstra, Thomas Gleixner, Ingo Molnar, kernel-dev
On Sat, Mar 30, 2024 at 06:57:06AM -0300, Thadeu Lima de Souza Cascardo wrote:
> On Fri, Mar 29, 2024 at 01:50:11PM +0100, Greg KH wrote:
> > On Mon, Mar 18, 2024 at 10:39:04AM -0300, Thadeu Lima de Souza Cascardo wrote:
> > > Otherwise, we see warnings like this:
> > >
> > > [ 0.000000][ T0] ------------[ cut here ]------------
> > > [ 0.000000][ T0] unexpected static_call insn opcode 0xf at kvm_vcpu_reload_apic_access_page+0x17/0x30
> > > [ 0.000000][ T0] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/static_call.c:88 __static_call_validate+0x68/0x70
> > > [ 0.000000][ T0] Modules linked in:
> > > [ 0.000000][ T0] CPU: 0 PID: 0 Comm: swapper Not tainted 5.15.151-00083-gf200c7260296 #68 fe3cb25cf78cb710722bb5acd1cadddd35172924
> > > [ 0.000000][ T0] RIP: 0010:__static_call_validate+0x68/0x70
> > > [ 0.000000][ T0] Code: 0f b6 4a 04 81 f1 c0 00 00 00 09 c1 74 cc 80 3d be 2c 02 02 00 75 c3 c6 05 b5 2c 02 02 01 48 c7 c7 38 4f c3 82 e8 e8 c8 09 00 <0f> 0b c3 00 00 cc cc 00 53 48 89 fb 48 63 15 31 71 06 02
> > > e8 b0 b8
> > > [ 0.000000][ T0] RSP: 0000:ffffffff82e03e70 EFLAGS: 00010046 ORIG_RAX: 0000000000000000
> > > [ 0.000000][ T0] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
> > > [ 0.000000][ T0] RDX: 0000000000000000 RSI: ffffffff82e03ce0 RDI: 0000000000000001
> > > [ 0.000000][ T0] RBP: 0000000000000001 R08: 00000000ffffffff R09: ffffffff82eaab70
> > > [ 0.000000][ T0] R10: ffffffff82e2e900 R11: 205d305420202020 R12: ffffffff82e51960
> > > [ 0.000000][ T0] R13: ffffffff81038987 R14: ffffffff81038987 R15: 0000000000000001
> > > [ 0.000000][ T0] FS: 0000000000000000(0000) GS:ffffffff83726000(0000) knlGS:0000000000000000
> > > [ 0.000000][ T0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > [ 0.000000][ T0] CR2: ffff888000014be8 CR3: 00000000037b2000 CR4: 00000000000000a0
> > > [ 0.000000][ T0] Call Trace:
> > > [ 0.000000][ T0] <TASK>
> > > [ 0.000000][ T0] ? __warn+0x75/0xe0
> > > [ 0.000000][ T0] ? report_bug+0x81/0xe0
> > > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > > [ 0.000000][ T0] ? early_fixup_exception+0x44/0xa0
> > > [ 0.000000][ T0] ? early_idt_handler_common+0x2f/0x40
> > > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > > [ 0.000000][ T0] ? __static_call_validate+0x68/0x70
> > > [ 0.000000][ T0] ? arch_static_call_transform+0x5c/0x90
> > > [ 0.000000][ T0] ? __static_call_init+0x1ec/0x230
> > > [ 0.000000][ T0] ? static_call_init+0x32/0x70
> > > [ 0.000000][ T0] ? setup_arch+0x36/0x4f0
> > > [ 0.000000][ T0] ? start_kernel+0x67/0x400
> > > [ 0.000000][ T0] ? secondary_startup_64_no_verify+0xb1/0xbb
> > > [ 0.000000][ T0] </TASK>
> > > [ 0.000000][ T0] ---[ end trace 8c8589c01f370686 ]---
> > >
> > >
> > >
> > > Peter Zijlstra (3):
> > > x86/alternatives: Introduce int3_emulate_jcc()
> > > x86/alternatives: Teach text_poke_bp() to patch Jcc.d32 instructions
> > > x86/static_call: Add support for Jcc tail-calls
> > >
> > > arch/x86/include/asm/text-patching.h | 31 +++++++++++++++
> > > arch/x86/kernel/alternative.c | 56 +++++++++++++++++++++++-----
> > > arch/x86/kernel/kprobes/core.c | 38 ++++---------------
> > > arch/x86/kernel/static_call.c | 49 ++++++++++++++++++++++--
> > > 4 files changed, 132 insertions(+), 42 deletions(-)
> >
> > Why is there a v2 series here? Are the ones I just took not correct?
> >
> > confused,
> >
> > greg k-h
>
> Because Sasha questioned the presence of the first 2 patches in the series
> while they were not backported to 6.1. Then, I looked at the 6.1 backport for
> reference and determined they were not really necessary if I picked the same
> changes that the 6.1 backport applied.
So is what I queued up correct or not?
still confused,
greg k-h
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 5.15 v2 0/3] Support static calls with LLVM-built kernels
2024-03-30 10:11 ` Greg KH
@ 2024-03-30 18:10 ` Thadeu Lima de Souza Cascardo
0 siblings, 0 replies; 8+ messages in thread
From: Thadeu Lima de Souza Cascardo @ 2024-03-30 18:10 UTC (permalink / raw)
To: Greg KH; +Cc: stable, Peter Zijlstra, Thomas Gleixner, Ingo Molnar, kernel-dev
On Sat, Mar 30, 2024 at 11:11:14AM +0100, Greg KH wrote:
> On Sat, Mar 30, 2024 at 06:57:06AM -0300, Thadeu Lima de Souza Cascardo wrote:
> > On Fri, Mar 29, 2024 at 01:50:11PM +0100, Greg KH wrote:
> > > On Mon, Mar 18, 2024 at 10:39:04AM -0300, Thadeu Lima de Souza Cascardo wrote:
> > > > Otherwise, we see warnings like this:
> > > >
> > > > [ 0.000000][ T0] ------------[ cut here ]------------
> > > > [ 0.000000][ T0] unexpected static_call insn opcode 0xf at kvm_vcpu_reload_apic_access_page+0x17/0x30
> > > > [ 0.000000][ T0] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/static_call.c:88 __static_call_validate+0x68/0x70
> > > > [ 0.000000][ T0] Modules linked in:
> > > > [ 0.000000][ T0] CPU: 0 PID: 0 Comm: swapper Not tainted 5.15.151-00083-gf200c7260296 #68 fe3cb25cf78cb710722bb5acd1cadddd35172924
> > > > [ 0.000000][ T0] RIP: 0010:__static_call_validate+0x68/0x70
> > > > [ 0.000000][ T0] Code: 0f b6 4a 04 81 f1 c0 00 00 00 09 c1 74 cc 80 3d be 2c 02 02 00 75 c3 c6 05 b5 2c 02 02 01 48 c7 c7 38 4f c3 82 e8 e8 c8 09 00 <0f> 0b c3 00 00 cc cc 00 53 48 89 fb 48 63 15 31 71 06 02
> > > > e8 b0 b8
> > > > [ 0.000000][ T0] RSP: 0000:ffffffff82e03e70 EFLAGS: 00010046 ORIG_RAX: 0000000000000000
> > > > [ 0.000000][ T0] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
> > > > [ 0.000000][ T0] RDX: 0000000000000000 RSI: ffffffff82e03ce0 RDI: 0000000000000001
> > > > [ 0.000000][ T0] RBP: 0000000000000001 R08: 00000000ffffffff R09: ffffffff82eaab70
> > > > [ 0.000000][ T0] R10: ffffffff82e2e900 R11: 205d305420202020 R12: ffffffff82e51960
> > > > [ 0.000000][ T0] R13: ffffffff81038987 R14: ffffffff81038987 R15: 0000000000000001
> > > > [ 0.000000][ T0] FS: 0000000000000000(0000) GS:ffffffff83726000(0000) knlGS:0000000000000000
> > > > [ 0.000000][ T0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > > [ 0.000000][ T0] CR2: ffff888000014be8 CR3: 00000000037b2000 CR4: 00000000000000a0
> > > > [ 0.000000][ T0] Call Trace:
> > > > [ 0.000000][ T0] <TASK>
> > > > [ 0.000000][ T0] ? __warn+0x75/0xe0
> > > > [ 0.000000][ T0] ? report_bug+0x81/0xe0
> > > > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > > > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > > > [ 0.000000][ T0] ? early_fixup_exception+0x44/0xa0
> > > > [ 0.000000][ T0] ? early_idt_handler_common+0x2f/0x40
> > > > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > > > [ 0.000000][ T0] ? kvm_vcpu_reload_apic_access_page+0x17/0x30
> > > > [ 0.000000][ T0] ? __static_call_validate+0x68/0x70
> > > > [ 0.000000][ T0] ? arch_static_call_transform+0x5c/0x90
> > > > [ 0.000000][ T0] ? __static_call_init+0x1ec/0x230
> > > > [ 0.000000][ T0] ? static_call_init+0x32/0x70
> > > > [ 0.000000][ T0] ? setup_arch+0x36/0x4f0
> > > > [ 0.000000][ T0] ? start_kernel+0x67/0x400
> > > > [ 0.000000][ T0] ? secondary_startup_64_no_verify+0xb1/0xbb
> > > > [ 0.000000][ T0] </TASK>
> > > > [ 0.000000][ T0] ---[ end trace 8c8589c01f370686 ]---
> > > >
> > > >
> > > >
> > > > Peter Zijlstra (3):
> > > > x86/alternatives: Introduce int3_emulate_jcc()
> > > > x86/alternatives: Teach text_poke_bp() to patch Jcc.d32 instructions
> > > > x86/static_call: Add support for Jcc tail-calls
> > > >
> > > > arch/x86/include/asm/text-patching.h | 31 +++++++++++++++
> > > > arch/x86/kernel/alternative.c | 56 +++++++++++++++++++++++-----
> > > > arch/x86/kernel/kprobes/core.c | 38 ++++---------------
> > > > arch/x86/kernel/static_call.c | 49 ++++++++++++++++++++++--
> > > > 4 files changed, 132 insertions(+), 42 deletions(-)
> > >
> > > Why is there a v2 series here? Are the ones I just took not correct?
> > >
> > > confused,
> > >
> > > greg k-h
> >
> > Because Sasha questioned the presence of the first 2 patches in the series
> > while they were not backported to 6.1. Then, I looked at the 6.1 backport for
> > reference and determined they were not really necessary if I picked the same
> > changes that the 6.1 backport applied.
>
> So is what I queued up correct or not?
>
> still confused,
>
> greg k-h
>
Either version are good. I understand there is a preference for v2 since it
doesn't include a change that was not applied in a later series, 6.1.y.
Cascardo.
^ permalink raw reply [flat|nested] 8+ messages in thread