[PATCH 0/3] Fix and unify call thunks assembly snippets

[PATCH 0/3] Fix and unify call thunks assembly snippets

[Uros Bizjak]

Currently INCREMENT_CALL_DEPTH and thunk debug macros explicitly
define %gs: segment register prefix for their percpu variables.
This is not compatible with !CONFIG_SMP, which requires non-prefixed
percpu variables.

Contrary to alternatives, relocations are currently not supported in
call thunk templates. Support for relocations will be needed when
PER_CPU_VAR macro switches to %rip-relative addressing.

Due to unsupported relocations, two variants of INCREMENT_CALL_DEPTH
macro are needed, ASM_ prefixed that allows relocations and
non-prefixed version that allows only absolute addresses.

The following patch series fixes above issues by

a) Moving call thunk template to its own callthunks-tmpl.S assembly file
where PER_CPU_VAR macro from percpu.h can be used to conditionally
use %gs: segment register prefix, depending on CONFIG_SMP.

b) Implementing minimal support for relocations when copying call thunk
template from its storage location to handle %rip-relative addresses.

c) Fixing call thunks debug macros to use PER_CPU_VAR macro from
percpu.h to conditionally use %gs: segment register prefix, depending
on CONFIG_SMP.

d) Unifying ASM_ prefixed assembly macros with their non-prefixed
variants. With support of %rip-relative relocations in place, call
thunk templates allow %rip-relative addressing, so unified assembly
snippet can be used everywhere.

The patch is independent of main percpu series in -tip tree.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>

Uros Bizjak (3):
  x86/callthunks: Move call thunk template to .S file
  x86/callthunks: Handle %rip-relative relocations in call thunk
    template
  x86/callthunks: Fix and unify call thunks assembly snippets

 arch/x86/include/asm/nospec-branch.h | 23 +++------
 arch/x86/kernel/Makefile             |  2 +-
 arch/x86/kernel/callthunks-tmpl.S    | 11 +++++
 arch/x86/kernel/callthunks.c         | 73 +++++++++++++++++++++-------
 4 files changed, 75 insertions(+), 34 deletions(-)
 create mode 100644 arch/x86/kernel/callthunks-tmpl.S

-- 
2.41.0

[PATCH 1/3] x86/callthunks: Move call thunk template to .S file

[Uros Bizjak]

Currently INCREMENT_CALL_DEPTH explicitly defines %gs: segment
register prefix for its percpu variable. This is not compatible
with !CONFIG_SMP, which requires non-prefixed percpu variables.

Move call thunk template to its own callthunks-tmpl.S assembly file
where PER_CPU_VAR macro from percpu.h can be used to conditionally
use %gs: segment register prefix, depending on CONFIG_SMP.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
---
 arch/x86/kernel/Makefile          |  2 +-
 arch/x86/kernel/callthunks-tmpl.S | 11 +++++++++++
 arch/x86/kernel/callthunks.c      | 10 ----------
 3 files changed, 12 insertions(+), 11 deletions(-)
 create mode 100644 arch/x86/kernel/callthunks-tmpl.S

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 3269a0e23d3a..6b6b68ef4c3b 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -143,7 +143,7 @@ obj-$(CONFIG_AMD_MEM_ENCRYPT)		+= sev.o
 
 obj-$(CONFIG_CFI_CLANG)			+= cfi.o
 
-obj-$(CONFIG_CALL_THUNKS)		+= callthunks.o
+obj-$(CONFIG_CALL_THUNKS)		+= callthunks.o callthunks-tmpl.o
 
 obj-$(CONFIG_X86_CET)			+= cet.o
 
diff --git a/arch/x86/kernel/callthunks-tmpl.S b/arch/x86/kernel/callthunks-tmpl.S
new file mode 100644
index 000000000000..e82c473bd1b1
--- /dev/null
+++ b/arch/x86/kernel/callthunks-tmpl.S
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <asm/nospec-branch.h>
+
+	.section .rodata
+	.global skl_call_thunk_template
+	.global skl_call_thunk_tail
+
+skl_call_thunk_template:
+	INCREMENT_CALL_DEPTH
+skl_call_thunk_tail:
diff --git a/arch/x86/kernel/callthunks.c b/arch/x86/kernel/callthunks.c
index e9ad518a5003..d0922cf94c90 100644
--- a/arch/x86/kernel/callthunks.c
+++ b/arch/x86/kernel/callthunks.c
@@ -62,16 +62,6 @@ static const struct core_text builtin_coretext = {
 	.name = "builtin",
 };
 
-asm (
-	".pushsection .rodata				\n"
-	".global skl_call_thunk_template		\n"
-	"skl_call_thunk_template:			\n"
-		__stringify(INCREMENT_CALL_DEPTH)"	\n"
-	".global skl_call_thunk_tail			\n"
-	"skl_call_thunk_tail:				\n"
-	".popsection					\n"
-);
-
 extern u8 skl_call_thunk_template[];
 extern u8 skl_call_thunk_tail[];
 
-- 
2.41.0

[PATCH 2/3] x86/callthunks: Handle %rip-relative relocations in call thunk template

[Uros Bizjak]

Contrary to alternatives, relocations are currently not supported in
call thunk templates.  Implement minimal support for relocations
when copying template from its storage location to handle %rip-relative
addresses.

Support for relocations will be needed when PER_CPU_VAR macro switches
to %rip-relative addressing.

The patch allows unification of ASM_INCREMENT_CALL_DEPTH, which already
uses PER_CPU_VAR macro, with INCREMENT_CALL_DEPTH, used in call thunk
template, which is currently limited to use absolute address.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
---
 arch/x86/kernel/callthunks.c | 63 ++++++++++++++++++++++++++++++++----
 1 file changed, 56 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/callthunks.c b/arch/x86/kernel/callthunks.c
index d0922cf94c90..bda09d82bff7 100644
--- a/arch/x86/kernel/callthunks.c
+++ b/arch/x86/kernel/callthunks.c
@@ -24,6 +24,8 @@
 
 static int __initdata_or_module debug_callthunks;
 
+#define MAX_PATCH_LEN (255-1)
+
 #define prdbg(fmt, args...)					\
 do {								\
 	if (debug_callthunks)					\
@@ -166,13 +168,51 @@ static const u8 nops[] = {
 	0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
 };
 
+#define apply_reloc_n(n_, p_, d_)				\
+	do {							\
+		s32 v = *(s##n_ *)(p_);				\
+		v += (d_);					\
+		BUG_ON((v >> 31) != (v >> (n_-1)));		\
+		*(s##n_ *)(p_) = (s##n_)v;			\
+	} while (0)
+
+static __always_inline
+void apply_reloc(int n, void *ptr, uintptr_t diff)
+{
+	switch (n) {
+	case 4: apply_reloc_n(32, ptr, diff); break;
+	default: BUG();
+	}
+}
+
+static void apply_relocation(u8 *buf, size_t len, u8 *dest, u8 *src)
+{
+	for (int next, i = 0; i < len; i = next) {
+		struct insn insn;
+
+		if (WARN_ON_ONCE(insn_decode_kernel(&insn, &buf[i])))
+			return;
+
+		next = i + insn.length;
+
+		if (insn_rip_relative(&insn))
+			apply_reloc(insn.displacement.nbytes,
+				    buf + i + insn_offset_displacement(&insn),
+				    src - dest);
+	}
+}
+
 static void *patch_dest(void *dest, bool direct)
 {
 	unsigned int tsize = SKL_TMPL_SIZE;
+	u8 insn_buff[MAX_PATCH_LEN];
 	u8 *pad = dest - tsize;
 
+	memcpy(insn_buff, skl_call_thunk_template, tsize);
+	apply_relocation(insn_buff, tsize, pad, skl_call_thunk_template);
+
 	/* Already patched? */
-	if (!bcmp(pad, skl_call_thunk_template, tsize))
+	if (!bcmp(pad, insn_buff, tsize))
 		return pad;
 
 	/* Ensure there are nops */
@@ -182,9 +222,9 @@ static void *patch_dest(void *dest, bool direct)
 	}
 
 	if (direct)
-		memcpy(pad, skl_call_thunk_template, tsize);
+		memcpy(pad, insn_buff, tsize);
 	else
-		text_poke_copy_locked(pad, skl_call_thunk_template, tsize, true);
+		text_poke_copy_locked(pad, insn_buff, tsize, true);
 	return pad;
 }
 
@@ -281,20 +321,26 @@ void *callthunks_translate_call_dest(void *dest)
 static bool is_callthunk(void *addr)
 {
 	unsigned int tmpl_size = SKL_TMPL_SIZE;
-	void *tmpl = skl_call_thunk_template;
+	u8 insn_buff[MAX_PATCH_LEN];
 	unsigned long dest;
+	u8 *pad;
 
 	dest = roundup((unsigned long)addr, CONFIG_FUNCTION_ALIGNMENT);
 	if (!thunks_initialized || skip_addr((void *)dest))
 		return false;
 
-	return !bcmp((void *)(dest - tmpl_size), tmpl, tmpl_size);
+	*pad = dest - tmpl_size;
+
+	memcpy(insn_buff, skl_call_thunk_template, tmpl_size);
+	apply_relocation(insn_buff, tmpl_size, pad, skl_call_thunk_template);
+
+	return !bcmp(pad, insn_buff, tmpl_size);
 }
 
 int x86_call_depth_emit_accounting(u8 **pprog, void *func)
 {
 	unsigned int tmpl_size = SKL_TMPL_SIZE;
-	void *tmpl = skl_call_thunk_template;
+	u8 insn_buff[MAX_PATCH_LEN];
 
 	if (!thunks_initialized)
 		return 0;
@@ -303,7 +349,10 @@ int x86_call_depth_emit_accounting(u8 **pprog, void *func)
 	if (func && is_callthunk(func))
 		return 0;
 
-	memcpy(*pprog, tmpl, tmpl_size);
+	memcpy(insn_buff, skl_call_thunk_template, tmpl_size);
+	apply_relocation(insn_buff, tmpl_size, *pprog, skl_call_thunk_template);
+
+	memcpy(*pprog, insn_buff, tmpl_size);
 	*pprog += tmpl_size;
 	return tmpl_size;
 }
-- 
2.41.0

Re: [PATCH 2/3] x86/callthunks: Handle %rip-relative relocations in call thunk template

[Peter Zijlstra]

On Thu, Nov 02, 2023 at 12:25:47PM +0100, Uros Bizjak wrote:

> @@ -166,13 +168,51 @@ static const u8 nops[] = {
>  	0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
>  };
>  
> +#define apply_reloc_n(n_, p_, d_)				\
> +	do {							\
> +		s32 v = *(s##n_ *)(p_);				\
> +		v += (d_);					\
> +		BUG_ON((v >> 31) != (v >> (n_-1)));		\
> +		*(s##n_ *)(p_) = (s##n_)v;			\
> +	} while (0)
> +
> +static __always_inline
> +void apply_reloc(int n, void *ptr, uintptr_t diff)
> +{
> +	switch (n) {
> +	case 4: apply_reloc_n(32, ptr, diff); break;
> +	default: BUG();
> +	}
> +}
> +
> +static void apply_relocation(u8 *buf, size_t len, u8 *dest, u8 *src)
> +{
> +	for (int next, i = 0; i < len; i = next) {
> +		struct insn insn;
> +
> +		if (WARN_ON_ONCE(insn_decode_kernel(&insn, &buf[i])))
> +			return;
> +
> +		next = i + insn.length;
> +
> +		if (insn_rip_relative(&insn))
> +			apply_reloc(insn.displacement.nbytes,
> +				    buf + i + insn_offset_displacement(&insn),
> +				    src - dest);
> +	}
> +}

Isn't it simpler to use apply_relocation() from alternative.c?

Remove static, add decl, stuff like that?

Re: [PATCH 2/3] x86/callthunks: Handle %rip-relative relocations in call thunk template

[Uros Bizjak]

On Thu, Nov 2, 2023 at 12:44 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Thu, Nov 02, 2023 at 12:25:47PM +0100, Uros Bizjak wrote:
>
> > @@ -166,13 +168,51 @@ static const u8 nops[] = {
> >       0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
> >  };
> >
> > +#define apply_reloc_n(n_, p_, d_)                            \
> > +     do {                                                    \
> > +             s32 v = *(s##n_ *)(p_);                         \
> > +             v += (d_);                                      \
> > +             BUG_ON((v >> 31) != (v >> (n_-1)));             \
> > +             *(s##n_ *)(p_) = (s##n_)v;                      \
> > +     } while (0)
> > +
> > +static __always_inline
> > +void apply_reloc(int n, void *ptr, uintptr_t diff)
> > +{
> > +     switch (n) {
> > +     case 4: apply_reloc_n(32, ptr, diff); break;
> > +     default: BUG();
> > +     }
> > +}
> > +
> > +static void apply_relocation(u8 *buf, size_t len, u8 *dest, u8 *src)
> > +{
> > +     for (int next, i = 0; i < len; i = next) {
> > +             struct insn insn;
> > +
> > +             if (WARN_ON_ONCE(insn_decode_kernel(&insn, &buf[i])))
> > +                     return;
> > +
> > +             next = i + insn.length;
> > +
> > +             if (insn_rip_relative(&insn))
> > +                     apply_reloc(insn.displacement.nbytes,
> > +                                 buf + i + insn_offset_displacement(&insn),
> > +                                 src - dest);
> > +     }
> > +}
>
> Isn't it simpler to use apply_relocation() from alternative.c?

Yes, I was looking at that function, but somehow thought that it is a
bit overkill here, since we just need a %rip-relative reloc.

> Remove static, add decl, stuff like that?

On second thought, you are right. Should I move the above function
somewhere (reloc.c?) , or can I just use it from alternative.c and add
decl (where?) ?

Thanks,
Uros.

Re: [PATCH 2/3] x86/callthunks: Handle %rip-relative relocations in call thunk template

[Peter Zijlstra]

On Thu, Nov 02, 2023 at 12:50:01PM +0100, Uros Bizjak wrote:

> > Remove static, add decl, stuff like that?
> 
> On second thought, you are right. Should I move the above function
> somewhere (reloc.c?) , or can I just use it from alternative.c and add
> decl (where?) ?

Yeah, leave it there for now, perhaps asm/text-patching.h ?

Re: [PATCH 2/3] x86/callthunks: Handle %rip-relative relocations in call thunk template

[Uros Bizjak]

[-- Attachment #1: Type: text/plain, Size: 511 bytes --]

On Thu, Nov 2, 2023 at 12:56 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Thu, Nov 02, 2023 at 12:50:01PM +0100, Uros Bizjak wrote:
>
> > > Remove static, add decl, stuff like that?
> >
> > On second thought, you are right. Should I move the above function
> > somewhere (reloc.c?) , or can I just use it from alternative.c and add
> > decl (where?) ?
>
> Yeah, leave it there for now, perhaps asm/text-patching.h ?

The new version boots OK and looks like the attached patch.

Uros.

[-- Attachment #2: reloc.diff.txt --]
[-- Type: text/plain, Size: 3581 bytes --]

diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index 29832c338cdc..ba8d900f3ebe 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -18,6 +18,8 @@ static inline void apply_paravirt(struct paravirt_patch_site *start,
 #define __parainstructions_end	NULL
 #endif
 
+void apply_relocation(u8 *buf, size_t len, u8 *dest, u8 *src, size_t src_len);
+
 /*
  * Currently, the max observed size in the kernel code is
  * JUMP_LABEL_NOP_SIZE/RELATIVEJUMP_SIZE, which are 5.
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 73be3931e4f0..66140c54d4f6 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -325,8 +325,7 @@ bool need_reloc(unsigned long offset, u8 *src, size_t src_len)
 	return (target < src || target > src + src_len);
 }
 
-static void __init_or_module noinline
-apply_relocation(u8 *buf, size_t len, u8 *dest, u8 *src, size_t src_len)
+void apply_relocation(u8 *buf, size_t len, u8 *dest, u8 *src, size_t src_len)
 {
 	int prev, target = 0;
 
diff --git a/arch/x86/kernel/callthunks.c b/arch/x86/kernel/callthunks.c
index d0922cf94c90..832eaec36e2b 100644
--- a/arch/x86/kernel/callthunks.c
+++ b/arch/x86/kernel/callthunks.c
@@ -24,6 +24,8 @@
 
 static int __initdata_or_module debug_callthunks;
 
+#define MAX_PATCH_LEN (255-1)
+
 #define prdbg(fmt, args...)					\
 do {								\
 	if (debug_callthunks)					\
@@ -169,10 +171,15 @@ static const u8 nops[] = {
 static void *patch_dest(void *dest, bool direct)
 {
 	unsigned int tsize = SKL_TMPL_SIZE;
+	u8 insn_buff[MAX_PATCH_LEN];
 	u8 *pad = dest - tsize;
 
+	memcpy(insn_buff, skl_call_thunk_template, tsize);
+	apply_relocation(insn_buff, tsize, pad,
+			 skl_call_thunk_template, tsize);
+
 	/* Already patched? */
-	if (!bcmp(pad, skl_call_thunk_template, tsize))
+	if (!bcmp(pad, insn_buff, tsize))
 		return pad;
 
 	/* Ensure there are nops */
@@ -182,9 +189,9 @@ static void *patch_dest(void *dest, bool direct)
 	}
 
 	if (direct)
-		memcpy(pad, skl_call_thunk_template, tsize);
+		memcpy(pad, insn_buff, tsize);
 	else
-		text_poke_copy_locked(pad, skl_call_thunk_template, tsize, true);
+		text_poke_copy_locked(pad, insn_buff, tsize, true);
 	return pad;
 }
 
@@ -281,20 +288,27 @@ void *callthunks_translate_call_dest(void *dest)
 static bool is_callthunk(void *addr)
 {
 	unsigned int tmpl_size = SKL_TMPL_SIZE;
-	void *tmpl = skl_call_thunk_template;
+	u8 insn_buff[MAX_PATCH_LEN];
 	unsigned long dest;
+	u8 *pad;
 
 	dest = roundup((unsigned long)addr, CONFIG_FUNCTION_ALIGNMENT);
 	if (!thunks_initialized || skip_addr((void *)dest))
 		return false;
 
-	return !bcmp((void *)(dest - tmpl_size), tmpl, tmpl_size);
+	*pad = dest - tmpl_size;
+
+	memcpy(insn_buff, skl_call_thunk_template, tmpl_size);
+	apply_relocation(insn_buff, tmpl_size, pad,
+			 skl_call_thunk_template, tmpl_size);
+
+	return !bcmp(pad, insn_buff, tmpl_size);
 }
 
 int x86_call_depth_emit_accounting(u8 **pprog, void *func)
 {
 	unsigned int tmpl_size = SKL_TMPL_SIZE;
-	void *tmpl = skl_call_thunk_template;
+	u8 insn_buff[MAX_PATCH_LEN];
 
 	if (!thunks_initialized)
 		return 0;
@@ -303,7 +317,11 @@ int x86_call_depth_emit_accounting(u8 **pprog, void *func)
 	if (func && is_callthunk(func))
 		return 0;
 
-	memcpy(*pprog, tmpl, tmpl_size);
+	memcpy(insn_buff, skl_call_thunk_template, tmpl_size);
+	apply_relocation(insn_buff, tmpl_size, *pprog,
+			 skl_call_thunk_template, tmpl_size);
+
+	memcpy(*pprog, insn_buff, tmpl_size);
 	*pprog += tmpl_size;
 	return tmpl_size;
 }

[PATCH 3/3] x86/callthunks: Fix and unify call thunks assembly snippets

[Uros Bizjak]

Currently thunk debug macros explicitly define %gs: segment register
prefix for their percpu variables. This is not compatible with
!CONFIG_SMP, which requires non-prefixed percpu variables.

Fix call thunks debug macros to use PER_CPU_VAR macro from percpu.h
to conditionally use %gs: segment register prefix, depending on
CONFIG_SMP.

Finally, unify ASM_ prefixed assembly macros with their non-prefixed
variants. With support of %rip-relative relocations in place, call
thunk templates allow %rip-relative addressing, so unified assembly
snippet can be used everywhere.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
---
 arch/x86/include/asm/nospec-branch.h | 23 +++++++----------------
 1 file changed, 7 insertions(+), 16 deletions(-)

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index f93e9b96927a..6f677be6bdb9 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -59,13 +59,13 @@
 
 #ifdef CONFIG_CALL_THUNKS_DEBUG
 # define CALL_THUNKS_DEBUG_INC_CALLS				\
-	incq	%gs:__x86_call_count;
+	incq	PER_CPU_VAR(__x86_call_count);
 # define CALL_THUNKS_DEBUG_INC_RETS				\
-	incq	%gs:__x86_ret_count;
+	incq	PER_CPU_VAR(__x86_ret_count);
 # define CALL_THUNKS_DEBUG_INC_STUFFS				\
-	incq	%gs:__x86_stuffs_count;
+	incq	PER_CPU_VAR(__x86_stuffs_count);
 # define CALL_THUNKS_DEBUG_INC_CTXSW				\
-	incq	%gs:__x86_ctxsw_count;
+	incq	PER_CPU_VAR(__x86_ctxsw_count);
 #else
 # define CALL_THUNKS_DEBUG_INC_CALLS
 # define CALL_THUNKS_DEBUG_INC_RETS
@@ -80,9 +80,6 @@
 #define CREDIT_CALL_DEPTH					\
 	movq	$-1, PER_CPU_VAR(pcpu_hot + X86_call_depth);
 
-#define ASM_CREDIT_CALL_DEPTH					\
-	movq	$-1, PER_CPU_VAR(pcpu_hot + X86_call_depth);
-
 #define RESET_CALL_DEPTH					\
 	xor	%eax, %eax;					\
 	bts	$63, %rax;					\
@@ -95,20 +92,14 @@
 	CALL_THUNKS_DEBUG_INC_CALLS
 
 #define INCREMENT_CALL_DEPTH					\
-	sarq	$5, %gs:pcpu_hot + X86_call_depth;		\
-	CALL_THUNKS_DEBUG_INC_CALLS
-
-#define ASM_INCREMENT_CALL_DEPTH				\
 	sarq	$5, PER_CPU_VAR(pcpu_hot + X86_call_depth);	\
 	CALL_THUNKS_DEBUG_INC_CALLS
 
 #else
 #define CREDIT_CALL_DEPTH
-#define ASM_CREDIT_CALL_DEPTH
 #define RESET_CALL_DEPTH
-#define INCREMENT_CALL_DEPTH
-#define ASM_INCREMENT_CALL_DEPTH
 #define RESET_CALL_DEPTH_FROM_CALL
+#define INCREMENT_CALL_DEPTH
 #endif
 
 /*
@@ -158,7 +149,7 @@
 	jnz	771b;					\
 	/* barrier for jnz misprediction */		\
 	lfence;						\
-	ASM_CREDIT_CALL_DEPTH				\
+	CREDIT_CALL_DEPTH				\
 	CALL_THUNKS_DEBUG_INC_CTXSW
 #else
 /*
@@ -311,7 +302,7 @@
 .macro CALL_DEPTH_ACCOUNT
 #ifdef CONFIG_CALL_DEPTH_TRACKING
 	ALTERNATIVE "",							\
-		    __stringify(ASM_INCREMENT_CALL_DEPTH), X86_FEATURE_CALL_DEPTH
+		    __stringify(INCREMENT_CALL_DEPTH), X86_FEATURE_CALL_DEPTH
 #endif
 .endm
 
-- 
2.41.0

Re: [PATCH 3/3] x86/callthunks: Fix and unify call thunks assembly snippets

[kernel test robot]

Hi Uros,

kernel test robot noticed the following build errors:

[auto build test ERROR on tip/x86/core]
[also build test ERROR on tip/master tip/auto-latest linus/master v6.6 next-20231103]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Uros-Bizjak/x86-callthunks-Move-call-thunk-template-to-S-file/20231102-193542
base:   tip/x86/core
patch link:    https://lore.kernel.org/r/20231102112850.3448745-4-ubizjak%40gmail.com
patch subject: [PATCH 3/3] x86/callthunks: Fix and unify call thunks assembly snippets
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20231105/202311051652.38OyamEq-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231105/202311051652.38OyamEq-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311051652.38OyamEq-lkp@intel.com/

All errors (new ones prefixed by >>):

   /tmp/ccwZh9MG.s: Assembler messages:
>> /tmp/ccwZh9MG.s:27: Error: junk `(pcpu_hot+16)' after expression
>> /tmp/ccwZh9MG.s:27: Error: junk `(__x86_call_count)' after expression

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki