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* [PATCH 0/2] x86: Avoid CONFIG_X86_X32_ABI=y with llvm-objcopy
@ 2022-03-14 19:48 ` Nathan Chancellor
  0 siblings, 0 replies; 10+ messages in thread
From: Nathan Chancellor @ 2022-03-14 19:48 UTC (permalink / raw)
  To: Peter Zijlstra, x86
  Cc: Andy Lutomirski, H. Peter Anvin, Nick Desaulniers,
	Masahiro Yamada, linux-kernel, alsa-devel, linux-fsdevel,
	linux-xfs, llvm, Nathan Chancellor

This series disables CONFIG_X86_X32_ABI=y with llvm-objcopy, which has
had two outstanding issues, which are further outlined in the second
patch:

https://github.com/ClangBuiltLinux/linux/issues/514
https://github.com/ClangBuiltLinux/linux/issues/1141

The first patch is from Masahiro, which moves the CONFIG_X86_X32_ABI
back into Kconfig proper. It was initially pushed as an RFC:

https://lore.kernel.org/r/20210227183910.221873-1-masahiroy@kernel.org/

The conclusion of that thread was that the check was still needed
because of the two issues above. However, with the introduction of
IBT, specifically commit 41c5ef31ad71 ("x86/ibt: Base IBT bits"), the
second issue linked above becomes visible with allmodconfig, which
heavily impacts automated testing.

The second patch builds on the first by just universally disabling
CONFIG_X86_X32_ABI when using llvm-objcopy at configuration time so that
neither issue is visible.

While it is unlikely that these issues will be fixed in LLVM, this could
eventually become a version check.

This is based on -tip x86/core and I would like for both patches to go
with the IBT changes so that there is no build breakage.

Masahiro Yamada (1):
  x86: Remove toolchain check for X32 ABI capability

Nathan Chancellor (1):
  x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy

 arch/x86/Kconfig                       | 13 +++++++------
 arch/x86/Makefile                      | 16 ----------------
 arch/x86/entry/syscalls/Makefile       |  2 +-
 arch/x86/include/asm/syscall_wrapper.h |  6 +++---
 arch/x86/include/asm/vdso.h            |  2 +-
 arch/x86/kernel/process_64.c           |  2 +-
 fs/fuse/ioctl.c                        |  2 +-
 fs/xfs/xfs_ioctl32.c                   |  2 +-
 sound/core/control_compat.c            | 16 ++++++++--------
 sound/core/pcm_compat.c                | 20 ++++++++++----------
 10 files changed, 33 insertions(+), 48 deletions(-)


base-commit: f8afc9d88e65d189653f363eacc1f3131216ef7c
-- 
2.35.1


^ permalink raw reply	[flat|nested] 10+ messages in thread
* [PATCH 0/2] x86: Avoid CONFIG_X86_X32_ABI=y with llvm-objcopy
@ 2022-03-14 19:48 ` Nathan Chancellor
  0 siblings, 0 replies; 10+ messages in thread
From: Nathan Chancellor @ 2022-03-14 19:48 UTC (permalink / raw)
  To: Peter Zijlstra, x86
  Cc: Nathan Chancellor, alsa-devel, Masahiro Yamada, llvm,
	Nick Desaulniers, linux-kernel, linux-xfs, Andy Lutomirski,
	H. Peter Anvin, linux-fsdevel

This series disables CONFIG_X86_X32_ABI=y with llvm-objcopy, which has
had two outstanding issues, which are further outlined in the second
patch:

https://github.com/ClangBuiltLinux/linux/issues/514
https://github.com/ClangBuiltLinux/linux/issues/1141

The first patch is from Masahiro, which moves the CONFIG_X86_X32_ABI
back into Kconfig proper. It was initially pushed as an RFC:

https://lore.kernel.org/r/20210227183910.221873-1-masahiroy@kernel.org/

The conclusion of that thread was that the check was still needed
because of the two issues above. However, with the introduction of
IBT, specifically commit 41c5ef31ad71 ("x86/ibt: Base IBT bits"), the
second issue linked above becomes visible with allmodconfig, which
heavily impacts automated testing.

The second patch builds on the first by just universally disabling
CONFIG_X86_X32_ABI when using llvm-objcopy at configuration time so that
neither issue is visible.

While it is unlikely that these issues will be fixed in LLVM, this could
eventually become a version check.

This is based on -tip x86/core and I would like for both patches to go
with the IBT changes so that there is no build breakage.

Masahiro Yamada (1):
  x86: Remove toolchain check for X32 ABI capability

Nathan Chancellor (1):
  x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy

 arch/x86/Kconfig                       | 13 +++++++------
 arch/x86/Makefile                      | 16 ----------------
 arch/x86/entry/syscalls/Makefile       |  2 +-
 arch/x86/include/asm/syscall_wrapper.h |  6 +++---
 arch/x86/include/asm/vdso.h            |  2 +-
 arch/x86/kernel/process_64.c           |  2 +-
 fs/fuse/ioctl.c                        |  2 +-
 fs/xfs/xfs_ioctl32.c                   |  2 +-
 sound/core/control_compat.c            | 16 ++++++++--------
 sound/core/pcm_compat.c                | 20 ++++++++++----------
 10 files changed, 33 insertions(+), 48 deletions(-)


base-commit: f8afc9d88e65d189653f363eacc1f3131216ef7c
-- 
2.35.1


^ permalink raw reply	[flat|nested] 10+ messages in thread
* [PATCH 1/2] x86: Remove toolchain check for X32 ABI capability
  2022-03-14 19:48 ` Nathan Chancellor
@ 2022-03-14 19:48   ` Nathan Chancellor
  -1 siblings, 0 replies; 10+ messages in thread
From: Nathan Chancellor @ 2022-03-14 19:48 UTC (permalink / raw)
  To: Peter Zijlstra, x86
  Cc: Andy Lutomirski, H. Peter Anvin, Nick Desaulniers,
	Masahiro Yamada, linux-kernel, alsa-devel, linux-fsdevel,
	linux-xfs, llvm, Nathan Chancellor

From: Masahiro Yamada <masahiroy@kernel.org>

Commit 0bf6276392e9 ("x32: Warn and disable rather than error if
binutils too old") added a small test in arch/x86/Makefile because
binutils 2.22 or newer is needed to properly support elf32-x86-64. This
check is no longer necessary, as the minimum supported version of
binutils is 2.23, which is enforced at configuration time with
scripts/min-tool-version.sh.

Remove this check and replace all uses of CONFIG_X86_X32 with
CONFIG_X86_X32_ABI, as two symbols are no longer necessary.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
[nathan: Rebase, fix up a few places where CONFIG_X86_X32 was still
         used, and simplify commit message to satisfy -tip requirements]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 arch/x86/Kconfig                       |  8 ++------
 arch/x86/Makefile                      | 16 ----------------
 arch/x86/entry/syscalls/Makefile       |  2 +-
 arch/x86/include/asm/syscall_wrapper.h |  6 +++---
 arch/x86/include/asm/vdso.h            |  2 +-
 arch/x86/kernel/process_64.c           |  2 +-
 fs/fuse/ioctl.c                        |  2 +-
 fs/xfs/xfs_ioctl32.c                   |  2 +-
 sound/core/control_compat.c            | 16 ++++++++--------
 sound/core/pcm_compat.c                | 20 ++++++++++----------
 10 files changed, 28 insertions(+), 48 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 870e0d10452d..b903bfcd713c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2861,7 +2861,7 @@ config IA32_AOUT
 	help
 	  Support old a.out binaries in the 32bit emulation.
 
-config X86_X32
+config X86_X32_ABI
 	bool "x32 ABI for 64-bit mode"
 	depends on X86_64
 	help
@@ -2870,10 +2870,6 @@ config X86_X32
 	  full 64-bit register file and wide data path while leaving
 	  pointers at 32 bits for smaller memory footprint.
 
-	  You will need a recent binutils (2.22 or later) with
-	  elf32_x86_64 support enabled to compile a kernel with this
-	  option set.
-
 config COMPAT_32
 	def_bool y
 	depends on IA32_EMULATION || X86_32
@@ -2882,7 +2878,7 @@ config COMPAT_32
 
 config COMPAT
 	def_bool y
-	depends on IA32_EMULATION || X86_X32
+	depends on IA32_EMULATION || X86_X32_ABI
 
 if COMPAT
 config COMPAT_FOR_U64_ALIGNMENT
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index f29c2c9c3216..63d50f65b828 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -152,22 +152,6 @@ else
         KBUILD_CFLAGS += -mcmodel=kernel
 endif
 
-ifdef CONFIG_X86_X32
-	x32_ld_ok := $(call try-run,\
-			/bin/echo -e '1: .quad 1b' | \
-			$(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
-			$(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMP.o" && \
-			$(LD) -m elf32_x86_64 "$$TMP.o" -o "$$TMP",y,n)
-        ifeq ($(x32_ld_ok),y)
-                CONFIG_X86_X32_ABI := y
-                KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
-                KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
-        else
-                $(warning CONFIG_X86_X32 enabled but no binutils support)
-        endif
-endif
-export CONFIG_X86_X32_ABI
-
 #
 # If the function graph tracer is used with mcount instead of fentry,
 # '-maccumulate-outgoing-args' is needed to prevent a GCC bug
diff --git a/arch/x86/entry/syscalls/Makefile b/arch/x86/entry/syscalls/Makefile
index 5b3efed0e4e8..7f3886eeb2ff 100644
--- a/arch/x86/entry/syscalls/Makefile
+++ b/arch/x86/entry/syscalls/Makefile
@@ -67,7 +67,7 @@ uapisyshdr-y			+= unistd_32.h unistd_64.h unistd_x32.h
 syshdr-y			+= syscalls_32.h
 syshdr-$(CONFIG_X86_64)		+= unistd_32_ia32.h unistd_64_x32.h
 syshdr-$(CONFIG_X86_64)		+= syscalls_64.h
-syshdr-$(CONFIG_X86_X32)	+= syscalls_x32.h
+syshdr-$(CONFIG_X86_X32_ABI)	+= syscalls_x32.h
 syshdr-$(CONFIG_XEN)		+= xen-hypercalls.h
 
 uapisyshdr-y	:= $(addprefix $(uapi)/, $(uapisyshdr-y))
diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index 6a2827d0681f..59358d1bf880 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -159,7 +159,7 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
 #endif /* CONFIG_IA32_EMULATION */
 
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /*
  * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware
  * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common
@@ -177,12 +177,12 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
 
 #define __X32_COMPAT_SYS_NI(name)					\
 	__SYS_NI(x64, compat_sys_##name)
-#else /* CONFIG_X86_X32 */
+#else /* CONFIG_X86_X32_ABI */
 #define __X32_COMPAT_SYS_STUB0(name)
 #define __X32_COMPAT_SYS_STUBx(x, name, ...)
 #define __X32_COMPAT_COND_SYSCALL(name)
 #define __X32_COMPAT_SYS_NI(name)
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 
 #ifdef CONFIG_COMPAT
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index 98aa103eb4ab..2963a2f5dbc4 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -37,7 +37,7 @@ struct vdso_image {
 extern const struct vdso_image vdso_image_64;
 #endif
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 extern const struct vdso_image vdso_image_x32;
 #endif
 
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 3402edec236c..e459253649be 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -681,7 +681,7 @@ void set_personality_64bit(void)
 
 static void __set_personality_x32(void)
 {
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	if (current->mm)
 		current->mm->context.flags = 0;
 
diff --git a/fs/fuse/ioctl.c b/fs/fuse/ioctl.c
index fbc09dab1f85..7143c85cc4aa 100644
--- a/fs/fuse/ioctl.c
+++ b/fs/fuse/ioctl.c
@@ -170,7 +170,7 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 #else
 	if (flags & FUSE_IOCTL_COMPAT) {
 		inarg.flags |= FUSE_IOCTL_32BIT;
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 		if (in_x32_syscall())
 			inarg.flags |= FUSE_IOCTL_COMPAT_X32;
 #endif
diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index 004ed2a251e8..ca25ed89b706 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -217,7 +217,7 @@ xfs_compat_ioc_fsbulkstat(
 	inumbers_fmt_pf		inumbers_func = xfs_fsinumbers_fmt_compat;
 	bulkstat_one_fmt_pf	bs_one_func = xfs_fsbulkstat_one_fmt_compat;
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	if (in_x32_syscall()) {
 		/*
 		 * ... but on x32 the input xfs_fsop_bulkreq has pointers
diff --git a/sound/core/control_compat.c b/sound/core/control_compat.c
index edff063e088d..d8a86d1a99d6 100644
--- a/sound/core/control_compat.c
+++ b/sound/core/control_compat.c
@@ -150,7 +150,7 @@ struct snd_ctl_elem_value32 {
         unsigned char reserved[128];
 };
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /* x32 has a different alignment for 64bit values from ia32 */
 struct snd_ctl_elem_value_x32 {
 	struct snd_ctl_elem_id id;
@@ -162,7 +162,7 @@ struct snd_ctl_elem_value_x32 {
 	} value;
 	unsigned char reserved[128];
 };
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 /* get the value type and count of the control */
 static int get_ctl_type(struct snd_card *card, struct snd_ctl_elem_id *id,
@@ -347,7 +347,7 @@ static int snd_ctl_elem_write_user_compat(struct snd_ctl_file *file,
 	return ctl_elem_write_user(file, data32, &data32->value);
 }
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 static int snd_ctl_elem_read_user_x32(struct snd_card *card,
 				      struct snd_ctl_elem_value_x32 __user *data32)
 {
@@ -359,7 +359,7 @@ static int snd_ctl_elem_write_user_x32(struct snd_ctl_file *file,
 {
 	return ctl_elem_write_user(file, data32, &data32->value);
 }
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 /* add or replace a user control */
 static int snd_ctl_elem_add_compat(struct snd_ctl_file *file,
@@ -418,10 +418,10 @@ enum {
 	SNDRV_CTL_IOCTL_ELEM_WRITE32 = _IOWR('U', 0x13, struct snd_ctl_elem_value32),
 	SNDRV_CTL_IOCTL_ELEM_ADD32 = _IOWR('U', 0x17, struct snd_ctl_elem_info32),
 	SNDRV_CTL_IOCTL_ELEM_REPLACE32 = _IOWR('U', 0x18, struct snd_ctl_elem_info32),
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	SNDRV_CTL_IOCTL_ELEM_READ_X32 = _IOWR('U', 0x12, struct snd_ctl_elem_value_x32),
 	SNDRV_CTL_IOCTL_ELEM_WRITE_X32 = _IOWR('U', 0x13, struct snd_ctl_elem_value_x32),
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 };
 
 static inline long snd_ctl_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg)
@@ -460,12 +460,12 @@ static inline long snd_ctl_ioctl_compat(struct file *file, unsigned int cmd, uns
 		return snd_ctl_elem_add_compat(ctl, argp, 0);
 	case SNDRV_CTL_IOCTL_ELEM_REPLACE32:
 		return snd_ctl_elem_add_compat(ctl, argp, 1);
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	case SNDRV_CTL_IOCTL_ELEM_READ_X32:
 		return snd_ctl_elem_read_user_x32(ctl->card, argp);
 	case SNDRV_CTL_IOCTL_ELEM_WRITE_X32:
 		return snd_ctl_elem_write_user_x32(ctl, argp);
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 	}
 
 	down_read(&snd_ioctl_rwsem);
diff --git a/sound/core/pcm_compat.c b/sound/core/pcm_compat.c
index e4e176854ce7..917c5b4f19d7 100644
--- a/sound/core/pcm_compat.c
+++ b/sound/core/pcm_compat.c
@@ -147,13 +147,13 @@ static int snd_pcm_ioctl_channel_info_compat(struct snd_pcm_substream *substream
 	return err;
 }
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /* X32 ABI has the same struct as x86-64 for snd_pcm_channel_info */
 static int snd_pcm_channel_info_user(struct snd_pcm_substream *substream,
 				     struct snd_pcm_channel_info __user *src);
 #define snd_pcm_ioctl_channel_info_x32(s, p)	\
 	snd_pcm_channel_info_user(s, p)
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 struct compat_snd_pcm_status64 {
 	snd_pcm_state_t state;
@@ -375,7 +375,7 @@ static int snd_pcm_ioctl_xfern_compat(struct snd_pcm_substream *substream,
 	return err;
 }
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /* X32 ABI has 64bit timespec and 64bit alignment */
 struct snd_pcm_mmap_status_x32 {
 	snd_pcm_state_t state;
@@ -468,7 +468,7 @@ static int snd_pcm_ioctl_sync_ptr_x32(struct snd_pcm_substream *substream,
 
 	return 0;
 }
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 #ifdef __BIG_ENDIAN
 typedef char __pad_before_u32[4];
@@ -560,10 +560,10 @@ enum {
 	SNDRV_PCM_IOCTL_READN_FRAMES32 = _IOR('A', 0x53, struct snd_xfern32),
 	SNDRV_PCM_IOCTL_STATUS_COMPAT64 = _IOR('A', 0x20, struct compat_snd_pcm_status64),
 	SNDRV_PCM_IOCTL_STATUS_EXT_COMPAT64 = _IOWR('A', 0x24, struct compat_snd_pcm_status64),
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	SNDRV_PCM_IOCTL_CHANNEL_INFO_X32 = _IOR('A', 0x32, struct snd_pcm_channel_info),
 	SNDRV_PCM_IOCTL_SYNC_PTR_X32 = _IOWR('A', 0x23, struct snd_pcm_sync_ptr_x32),
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 };
 
 static long snd_pcm_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg)
@@ -607,10 +607,10 @@ static long snd_pcm_ioctl_compat(struct file *file, unsigned int cmd, unsigned l
 	case __SNDRV_PCM_IOCTL_SYNC_PTR32:
 		return snd_pcm_common_ioctl(file, substream, cmd, argp);
 	case __SNDRV_PCM_IOCTL_SYNC_PTR64:
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 		if (in_x32_syscall())
 			return snd_pcm_ioctl_sync_ptr_x32(substream, argp);
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 		return snd_pcm_ioctl_sync_ptr_buggy(substream, argp);
 	case SNDRV_PCM_IOCTL_HW_REFINE32:
 		return snd_pcm_ioctl_hw_params_compat(substream, 1, argp);
@@ -642,10 +642,10 @@ static long snd_pcm_ioctl_compat(struct file *file, unsigned int cmd, unsigned l
 		return snd_pcm_status_user_compat64(substream, argp, false);
 	case SNDRV_PCM_IOCTL_STATUS_EXT_COMPAT64:
 		return snd_pcm_status_user_compat64(substream, argp, true);
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	case SNDRV_PCM_IOCTL_CHANNEL_INFO_X32:
 		return snd_pcm_ioctl_channel_info_x32(substream, argp);
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 	}
 
 	return -ENOIOCTLCMD;
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH 1/2] x86: Remove toolchain check for X32 ABI capability
@ 2022-03-14 19:48   ` Nathan Chancellor
  0 siblings, 0 replies; 10+ messages in thread
From: Nathan Chancellor @ 2022-03-14 19:48 UTC (permalink / raw)
  To: Peter Zijlstra, x86
  Cc: Nathan Chancellor, alsa-devel, Masahiro Yamada, llvm,
	Nick Desaulniers, linux-kernel, linux-xfs, Andy Lutomirski,
	H. Peter Anvin, linux-fsdevel

From: Masahiro Yamada <masahiroy@kernel.org>

Commit 0bf6276392e9 ("x32: Warn and disable rather than error if
binutils too old") added a small test in arch/x86/Makefile because
binutils 2.22 or newer is needed to properly support elf32-x86-64. This
check is no longer necessary, as the minimum supported version of
binutils is 2.23, which is enforced at configuration time with
scripts/min-tool-version.sh.

Remove this check and replace all uses of CONFIG_X86_X32 with
CONFIG_X86_X32_ABI, as two symbols are no longer necessary.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
[nathan: Rebase, fix up a few places where CONFIG_X86_X32 was still
         used, and simplify commit message to satisfy -tip requirements]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 arch/x86/Kconfig                       |  8 ++------
 arch/x86/Makefile                      | 16 ----------------
 arch/x86/entry/syscalls/Makefile       |  2 +-
 arch/x86/include/asm/syscall_wrapper.h |  6 +++---
 arch/x86/include/asm/vdso.h            |  2 +-
 arch/x86/kernel/process_64.c           |  2 +-
 fs/fuse/ioctl.c                        |  2 +-
 fs/xfs/xfs_ioctl32.c                   |  2 +-
 sound/core/control_compat.c            | 16 ++++++++--------
 sound/core/pcm_compat.c                | 20 ++++++++++----------
 10 files changed, 28 insertions(+), 48 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 870e0d10452d..b903bfcd713c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2861,7 +2861,7 @@ config IA32_AOUT
 	help
 	  Support old a.out binaries in the 32bit emulation.
 
-config X86_X32
+config X86_X32_ABI
 	bool "x32 ABI for 64-bit mode"
 	depends on X86_64
 	help
@@ -2870,10 +2870,6 @@ config X86_X32
 	  full 64-bit register file and wide data path while leaving
 	  pointers at 32 bits for smaller memory footprint.
 
-	  You will need a recent binutils (2.22 or later) with
-	  elf32_x86_64 support enabled to compile a kernel with this
-	  option set.
-
 config COMPAT_32
 	def_bool y
 	depends on IA32_EMULATION || X86_32
@@ -2882,7 +2878,7 @@ config COMPAT_32
 
 config COMPAT
 	def_bool y
-	depends on IA32_EMULATION || X86_X32
+	depends on IA32_EMULATION || X86_X32_ABI
 
 if COMPAT
 config COMPAT_FOR_U64_ALIGNMENT
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index f29c2c9c3216..63d50f65b828 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -152,22 +152,6 @@ else
         KBUILD_CFLAGS += -mcmodel=kernel
 endif
 
-ifdef CONFIG_X86_X32
-	x32_ld_ok := $(call try-run,\
-			/bin/echo -e '1: .quad 1b' | \
-			$(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
-			$(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMP.o" && \
-			$(LD) -m elf32_x86_64 "$$TMP.o" -o "$$TMP",y,n)
-        ifeq ($(x32_ld_ok),y)
-                CONFIG_X86_X32_ABI := y
-                KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
-                KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
-        else
-                $(warning CONFIG_X86_X32 enabled but no binutils support)
-        endif
-endif
-export CONFIG_X86_X32_ABI
-
 #
 # If the function graph tracer is used with mcount instead of fentry,
 # '-maccumulate-outgoing-args' is needed to prevent a GCC bug
diff --git a/arch/x86/entry/syscalls/Makefile b/arch/x86/entry/syscalls/Makefile
index 5b3efed0e4e8..7f3886eeb2ff 100644
--- a/arch/x86/entry/syscalls/Makefile
+++ b/arch/x86/entry/syscalls/Makefile
@@ -67,7 +67,7 @@ uapisyshdr-y			+= unistd_32.h unistd_64.h unistd_x32.h
 syshdr-y			+= syscalls_32.h
 syshdr-$(CONFIG_X86_64)		+= unistd_32_ia32.h unistd_64_x32.h
 syshdr-$(CONFIG_X86_64)		+= syscalls_64.h
-syshdr-$(CONFIG_X86_X32)	+= syscalls_x32.h
+syshdr-$(CONFIG_X86_X32_ABI)	+= syscalls_x32.h
 syshdr-$(CONFIG_XEN)		+= xen-hypercalls.h
 
 uapisyshdr-y	:= $(addprefix $(uapi)/, $(uapisyshdr-y))
diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index 6a2827d0681f..59358d1bf880 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -159,7 +159,7 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
 #endif /* CONFIG_IA32_EMULATION */
 
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /*
  * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware
  * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common
@@ -177,12 +177,12 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
 
 #define __X32_COMPAT_SYS_NI(name)					\
 	__SYS_NI(x64, compat_sys_##name)
-#else /* CONFIG_X86_X32 */
+#else /* CONFIG_X86_X32_ABI */
 #define __X32_COMPAT_SYS_STUB0(name)
 #define __X32_COMPAT_SYS_STUBx(x, name, ...)
 #define __X32_COMPAT_COND_SYSCALL(name)
 #define __X32_COMPAT_SYS_NI(name)
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 
 #ifdef CONFIG_COMPAT
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index 98aa103eb4ab..2963a2f5dbc4 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -37,7 +37,7 @@ struct vdso_image {
 extern const struct vdso_image vdso_image_64;
 #endif
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 extern const struct vdso_image vdso_image_x32;
 #endif
 
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 3402edec236c..e459253649be 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -681,7 +681,7 @@ void set_personality_64bit(void)
 
 static void __set_personality_x32(void)
 {
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	if (current->mm)
 		current->mm->context.flags = 0;
 
diff --git a/fs/fuse/ioctl.c b/fs/fuse/ioctl.c
index fbc09dab1f85..7143c85cc4aa 100644
--- a/fs/fuse/ioctl.c
+++ b/fs/fuse/ioctl.c
@@ -170,7 +170,7 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 #else
 	if (flags & FUSE_IOCTL_COMPAT) {
 		inarg.flags |= FUSE_IOCTL_32BIT;
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 		if (in_x32_syscall())
 			inarg.flags |= FUSE_IOCTL_COMPAT_X32;
 #endif
diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index 004ed2a251e8..ca25ed89b706 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -217,7 +217,7 @@ xfs_compat_ioc_fsbulkstat(
 	inumbers_fmt_pf		inumbers_func = xfs_fsinumbers_fmt_compat;
 	bulkstat_one_fmt_pf	bs_one_func = xfs_fsbulkstat_one_fmt_compat;
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	if (in_x32_syscall()) {
 		/*
 		 * ... but on x32 the input xfs_fsop_bulkreq has pointers
diff --git a/sound/core/control_compat.c b/sound/core/control_compat.c
index edff063e088d..d8a86d1a99d6 100644
--- a/sound/core/control_compat.c
+++ b/sound/core/control_compat.c
@@ -150,7 +150,7 @@ struct snd_ctl_elem_value32 {
         unsigned char reserved[128];
 };
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /* x32 has a different alignment for 64bit values from ia32 */
 struct snd_ctl_elem_value_x32 {
 	struct snd_ctl_elem_id id;
@@ -162,7 +162,7 @@ struct snd_ctl_elem_value_x32 {
 	} value;
 	unsigned char reserved[128];
 };
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 /* get the value type and count of the control */
 static int get_ctl_type(struct snd_card *card, struct snd_ctl_elem_id *id,
@@ -347,7 +347,7 @@ static int snd_ctl_elem_write_user_compat(struct snd_ctl_file *file,
 	return ctl_elem_write_user(file, data32, &data32->value);
 }
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 static int snd_ctl_elem_read_user_x32(struct snd_card *card,
 				      struct snd_ctl_elem_value_x32 __user *data32)
 {
@@ -359,7 +359,7 @@ static int snd_ctl_elem_write_user_x32(struct snd_ctl_file *file,
 {
 	return ctl_elem_write_user(file, data32, &data32->value);
 }
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 /* add or replace a user control */
 static int snd_ctl_elem_add_compat(struct snd_ctl_file *file,
@@ -418,10 +418,10 @@ enum {
 	SNDRV_CTL_IOCTL_ELEM_WRITE32 = _IOWR('U', 0x13, struct snd_ctl_elem_value32),
 	SNDRV_CTL_IOCTL_ELEM_ADD32 = _IOWR('U', 0x17, struct snd_ctl_elem_info32),
 	SNDRV_CTL_IOCTL_ELEM_REPLACE32 = _IOWR('U', 0x18, struct snd_ctl_elem_info32),
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	SNDRV_CTL_IOCTL_ELEM_READ_X32 = _IOWR('U', 0x12, struct snd_ctl_elem_value_x32),
 	SNDRV_CTL_IOCTL_ELEM_WRITE_X32 = _IOWR('U', 0x13, struct snd_ctl_elem_value_x32),
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 };
 
 static inline long snd_ctl_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg)
@@ -460,12 +460,12 @@ static inline long snd_ctl_ioctl_compat(struct file *file, unsigned int cmd, uns
 		return snd_ctl_elem_add_compat(ctl, argp, 0);
 	case SNDRV_CTL_IOCTL_ELEM_REPLACE32:
 		return snd_ctl_elem_add_compat(ctl, argp, 1);
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	case SNDRV_CTL_IOCTL_ELEM_READ_X32:
 		return snd_ctl_elem_read_user_x32(ctl->card, argp);
 	case SNDRV_CTL_IOCTL_ELEM_WRITE_X32:
 		return snd_ctl_elem_write_user_x32(ctl, argp);
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 	}
 
 	down_read(&snd_ioctl_rwsem);
diff --git a/sound/core/pcm_compat.c b/sound/core/pcm_compat.c
index e4e176854ce7..917c5b4f19d7 100644
--- a/sound/core/pcm_compat.c
+++ b/sound/core/pcm_compat.c
@@ -147,13 +147,13 @@ static int snd_pcm_ioctl_channel_info_compat(struct snd_pcm_substream *substream
 	return err;
 }
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /* X32 ABI has the same struct as x86-64 for snd_pcm_channel_info */
 static int snd_pcm_channel_info_user(struct snd_pcm_substream *substream,
 				     struct snd_pcm_channel_info __user *src);
 #define snd_pcm_ioctl_channel_info_x32(s, p)	\
 	snd_pcm_channel_info_user(s, p)
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 struct compat_snd_pcm_status64 {
 	snd_pcm_state_t state;
@@ -375,7 +375,7 @@ static int snd_pcm_ioctl_xfern_compat(struct snd_pcm_substream *substream,
 	return err;
 }
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /* X32 ABI has 64bit timespec and 64bit alignment */
 struct snd_pcm_mmap_status_x32 {
 	snd_pcm_state_t state;
@@ -468,7 +468,7 @@ static int snd_pcm_ioctl_sync_ptr_x32(struct snd_pcm_substream *substream,
 
 	return 0;
 }
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 #ifdef __BIG_ENDIAN
 typedef char __pad_before_u32[4];
@@ -560,10 +560,10 @@ enum {
 	SNDRV_PCM_IOCTL_READN_FRAMES32 = _IOR('A', 0x53, struct snd_xfern32),
 	SNDRV_PCM_IOCTL_STATUS_COMPAT64 = _IOR('A', 0x20, struct compat_snd_pcm_status64),
 	SNDRV_PCM_IOCTL_STATUS_EXT_COMPAT64 = _IOWR('A', 0x24, struct compat_snd_pcm_status64),
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	SNDRV_PCM_IOCTL_CHANNEL_INFO_X32 = _IOR('A', 0x32, struct snd_pcm_channel_info),
 	SNDRV_PCM_IOCTL_SYNC_PTR_X32 = _IOWR('A', 0x23, struct snd_pcm_sync_ptr_x32),
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 };
 
 static long snd_pcm_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg)
@@ -607,10 +607,10 @@ static long snd_pcm_ioctl_compat(struct file *file, unsigned int cmd, unsigned l
 	case __SNDRV_PCM_IOCTL_SYNC_PTR32:
 		return snd_pcm_common_ioctl(file, substream, cmd, argp);
 	case __SNDRV_PCM_IOCTL_SYNC_PTR64:
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 		if (in_x32_syscall())
 			return snd_pcm_ioctl_sync_ptr_x32(substream, argp);
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 		return snd_pcm_ioctl_sync_ptr_buggy(substream, argp);
 	case SNDRV_PCM_IOCTL_HW_REFINE32:
 		return snd_pcm_ioctl_hw_params_compat(substream, 1, argp);
@@ -642,10 +642,10 @@ static long snd_pcm_ioctl_compat(struct file *file, unsigned int cmd, unsigned l
 		return snd_pcm_status_user_compat64(substream, argp, false);
 	case SNDRV_PCM_IOCTL_STATUS_EXT_COMPAT64:
 		return snd_pcm_status_user_compat64(substream, argp, true);
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	case SNDRV_PCM_IOCTL_CHANNEL_INFO_X32:
 		return snd_pcm_ioctl_channel_info_x32(substream, argp);
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 	}
 
 	return -ENOIOCTLCMD;
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH 2/2] x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy
  2022-03-14 19:48 ` Nathan Chancellor
@ 2022-03-14 19:48   ` Nathan Chancellor
  -1 siblings, 0 replies; 10+ messages in thread
From: Nathan Chancellor @ 2022-03-14 19:48 UTC (permalink / raw)
  To: Peter Zijlstra, x86
  Cc: Andy Lutomirski, H. Peter Anvin, Nick Desaulniers,
	Masahiro Yamada, linux-kernel, alsa-devel, linux-fsdevel,
	linux-xfs, llvm, Nathan Chancellor

There are two outstanding issues with CONFIG_X86_X32_ABI and
llvm-objcopy, with similar root causes:

1. llvm-objcopy does not properly convert .note.gnu.property when going
   from x86_64 to x86_x32, resulting in a corrupted section when
   linking:

   https://github.com/ClangBuiltLinux/linux/issues/1141

2. llvm-objcopy produces corrupted compressed debug sections when going
   from x86_64 to x86_x32, also resulting in an error when linking:

   https://github.com/ClangBuiltLinux/linux/issues/514

After commit 41c5ef31ad71 ("x86/ibt: Base IBT bits"), the
.note.gnu.property section is always generated when
CONFIG_X86_KERNEL_IBT is enabled, which causes the first issue to become
visible with an allmodconfig build:

  ld.lld: error: arch/x86/entry/vdso/vclock_gettime-x32.o:(.note.gnu.property+0x1c): program property is too short

To avoid this error, do not allow CONFIG_X86_X32_ABI to be selected when
using llvm-objcopy. If the two issues ever get fixed in llvm-objcopy,
this can be turned into a feature check.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 arch/x86/Kconfig | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b903bfcd713c..0f0672d2c816 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2864,6 +2864,11 @@ config IA32_AOUT
 config X86_X32_ABI
 	bool "x32 ABI for 64-bit mode"
 	depends on X86_64
+	# llvm-objcopy does not convert x86_64 .note.gnu.property or
+	# compressed debug sections to x86_x32 properly:
+	# https://github.com/ClangBuiltLinux/linux/issues/514
+	# https://github.com/ClangBuiltLinux/linux/issues/1141
+	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
 	help
 	  Include code to run binaries for the x32 native 32-bit ABI
 	  for 64-bit processors.  An x32 process gets access to the
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH 2/2] x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy
@ 2022-03-14 19:48   ` Nathan Chancellor
  0 siblings, 0 replies; 10+ messages in thread
From: Nathan Chancellor @ 2022-03-14 19:48 UTC (permalink / raw)
  To: Peter Zijlstra, x86
  Cc: Nathan Chancellor, alsa-devel, Masahiro Yamada, llvm,
	Nick Desaulniers, linux-kernel, linux-xfs, Andy Lutomirski,
	H. Peter Anvin, linux-fsdevel

There are two outstanding issues with CONFIG_X86_X32_ABI and
llvm-objcopy, with similar root causes:

1. llvm-objcopy does not properly convert .note.gnu.property when going
   from x86_64 to x86_x32, resulting in a corrupted section when
   linking:

   https://github.com/ClangBuiltLinux/linux/issues/1141

2. llvm-objcopy produces corrupted compressed debug sections when going
   from x86_64 to x86_x32, also resulting in an error when linking:

   https://github.com/ClangBuiltLinux/linux/issues/514

After commit 41c5ef31ad71 ("x86/ibt: Base IBT bits"), the
.note.gnu.property section is always generated when
CONFIG_X86_KERNEL_IBT is enabled, which causes the first issue to become
visible with an allmodconfig build:

  ld.lld: error: arch/x86/entry/vdso/vclock_gettime-x32.o:(.note.gnu.property+0x1c): program property is too short

To avoid this error, do not allow CONFIG_X86_X32_ABI to be selected when
using llvm-objcopy. If the two issues ever get fixed in llvm-objcopy,
this can be turned into a feature check.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 arch/x86/Kconfig | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b903bfcd713c..0f0672d2c816 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2864,6 +2864,11 @@ config IA32_AOUT
 config X86_X32_ABI
 	bool "x32 ABI for 64-bit mode"
 	depends on X86_64
+	# llvm-objcopy does not convert x86_64 .note.gnu.property or
+	# compressed debug sections to x86_x32 properly:
+	# https://github.com/ClangBuiltLinux/linux/issues/514
+	# https://github.com/ClangBuiltLinux/linux/issues/1141
+	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
 	help
 	  Include code to run binaries for the x32 native 32-bit ABI
 	  for 64-bit processors.  An x32 process gets access to the
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/2] x86: Avoid CONFIG_X86_X32_ABI=y with llvm-objcopy
  2022-03-14 19:48 ` Nathan Chancellor
@ 2022-03-14 20:13   ` Peter Zijlstra
  -1 siblings, 0 replies; 10+ messages in thread
From: Peter Zijlstra @ 2022-03-14 20:13 UTC (permalink / raw)
  To: Nathan Chancellor
  Cc: x86, Andy Lutomirski, H. Peter Anvin, Nick Desaulniers,
	Masahiro Yamada, linux-kernel, alsa-devel, linux-fsdevel,
	linux-xfs, llvm

On Mon, Mar 14, 2022 at 12:48:40PM -0700, Nathan Chancellor wrote:
> This is based on -tip x86/core and I would like for both patches to go
> with the IBT changes so that there is no build breakage.
> 
> Masahiro Yamada (1):
>   x86: Remove toolchain check for X32 ABI capability
> 
> Nathan Chancellor (1):
>   x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy
> 

Mucho gracias, I was indeed seeing a lot of that. I was also in the
process of rebasing that tree, so I'll stick these on top.

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/2] x86: Avoid CONFIG_X86_X32_ABI=y with llvm-objcopy
@ 2022-03-14 20:13   ` Peter Zijlstra
  0 siblings, 0 replies; 10+ messages in thread
From: Peter Zijlstra @ 2022-03-14 20:13 UTC (permalink / raw)
  To: Nathan Chancellor
  Cc: alsa-devel, llvm, Masahiro Yamada, x86, Nick Desaulniers,
	linux-kernel, linux-xfs, Andy Lutomirski, H. Peter Anvin,
	linux-fsdevel

On Mon, Mar 14, 2022 at 12:48:40PM -0700, Nathan Chancellor wrote:
> This is based on -tip x86/core and I would like for both patches to go
> with the IBT changes so that there is no build breakage.
> 
> Masahiro Yamada (1):
>   x86: Remove toolchain check for X32 ABI capability
> 
> Nathan Chancellor (1):
>   x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy
> 

Mucho gracias, I was indeed seeing a lot of that. I was also in the
process of rebasing that tree, so I'll stick these on top.

^ permalink raw reply	[flat|nested] 10+ messages in thread
* [tip: x86/core] x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy
  2022-03-14 19:48   ` Nathan Chancellor
  (?)
@ 2022-03-15 10:43   ` tip-bot2 for Nathan Chancellor
  -1 siblings, 0 replies; 10+ messages in thread
From: tip-bot2 for Nathan Chancellor @ 2022-03-15 10:43 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: Nathan Chancellor, Peter Zijlstra (Intel), x86, linux-kernel

The following commit has been merged into the x86/core branch of tip:

Commit-ID:     aaeed6ecc1253ce1463fa1aca0b70a4ccbc9fa75
Gitweb:        https://git.kernel.org/tip/aaeed6ecc1253ce1463fa1aca0b70a4ccbc9fa75
Author:        Nathan Chancellor <nathan@kernel.org>
AuthorDate:    Mon, 14 Mar 2022 12:48:42 -07:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 15 Mar 2022 10:32:48 +01:00

x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy

There are two outstanding issues with CONFIG_X86_X32_ABI and
llvm-objcopy, with similar root causes:

1. llvm-objcopy does not properly convert .note.gnu.property when going
   from x86_64 to x86_x32, resulting in a corrupted section when
   linking:

   https://github.com/ClangBuiltLinux/linux/issues/1141

2. llvm-objcopy produces corrupted compressed debug sections when going
   from x86_64 to x86_x32, also resulting in an error when linking:

   https://github.com/ClangBuiltLinux/linux/issues/514

After commit 41c5ef31ad71 ("x86/ibt: Base IBT bits"), the
.note.gnu.property section is always generated when
CONFIG_X86_KERNEL_IBT is enabled, which causes the first issue to become
visible with an allmodconfig build:

  ld.lld: error: arch/x86/entry/vdso/vclock_gettime-x32.o:(.note.gnu.property+0x1c): program property is too short

To avoid this error, do not allow CONFIG_X86_X32_ABI to be selected when
using llvm-objcopy. If the two issues ever get fixed in llvm-objcopy,
this can be turned into a feature check.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220314194842.3452-3-nathan@kernel.org
---
 arch/x86/Kconfig | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b903bfc..0f0672d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2864,6 +2864,11 @@ config IA32_AOUT
 config X86_X32_ABI
 	bool "x32 ABI for 64-bit mode"
 	depends on X86_64
+	# llvm-objcopy does not convert x86_64 .note.gnu.property or
+	# compressed debug sections to x86_x32 properly:
+	# https://github.com/ClangBuiltLinux/linux/issues/514
+	# https://github.com/ClangBuiltLinux/linux/issues/1141
+	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
 	help
 	  Include code to run binaries for the x32 native 32-bit ABI
 	  for 64-bit processors.  An x32 process gets access to the

^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [tip: x86/core] x86: Remove toolchain check for X32 ABI capability
  2022-03-14 19:48   ` Nathan Chancellor
  (?)
@ 2022-03-15 10:43   ` tip-bot2 for Masahiro Yamada
  -1 siblings, 0 replies; 10+ messages in thread
From: tip-bot2 for Masahiro Yamada @ 2022-03-15 10:43 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: Masahiro Yamada, Nathan Chancellor, Peter Zijlstra (Intel),
	x86, linux-kernel

The following commit has been merged into the x86/core branch of tip:

Commit-ID:     83a44a4f47ad20997aebb311fc678a13cde391d7
Gitweb:        https://git.kernel.org/tip/83a44a4f47ad20997aebb311fc678a13cde391d7
Author:        Masahiro Yamada <masahiroy@kernel.org>
AuthorDate:    Mon, 14 Mar 2022 12:48:41 -07:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 15 Mar 2022 10:32:48 +01:00

x86: Remove toolchain check for X32 ABI capability

Commit 0bf6276392e9 ("x32: Warn and disable rather than error if
binutils too old") added a small test in arch/x86/Makefile because
binutils 2.22 or newer is needed to properly support elf32-x86-64. This
check is no longer necessary, as the minimum supported version of
binutils is 2.23, which is enforced at configuration time with
scripts/min-tool-version.sh.

Remove this check and replace all uses of CONFIG_X86_X32 with
CONFIG_X86_X32_ABI, as two symbols are no longer necessary.

[nathan: Rebase, fix up a few places where CONFIG_X86_X32 was still
         used, and simplify commit message to satisfy -tip requirements]

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220314194842.3452-2-nathan@kernel.org
---
 arch/x86/Kconfig                       |  8 ++------
 arch/x86/Makefile                      | 16 ----------------
 arch/x86/entry/syscalls/Makefile       |  2 +-
 arch/x86/include/asm/syscall_wrapper.h |  6 +++---
 arch/x86/include/asm/vdso.h            |  2 +-
 arch/x86/kernel/process_64.c           |  2 +-
 fs/fuse/ioctl.c                        |  2 +-
 fs/xfs/xfs_ioctl32.c                   |  2 +-
 sound/core/control_compat.c            | 16 ++++++++--------
 sound/core/pcm_compat.c                | 20 ++++++++++----------
 10 files changed, 28 insertions(+), 48 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 870e0d1..b903bfc 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2861,7 +2861,7 @@ config IA32_AOUT
 	help
 	  Support old a.out binaries in the 32bit emulation.
 
-config X86_X32
+config X86_X32_ABI
 	bool "x32 ABI for 64-bit mode"
 	depends on X86_64
 	help
@@ -2870,10 +2870,6 @@ config X86_X32
 	  full 64-bit register file and wide data path while leaving
 	  pointers at 32 bits for smaller memory footprint.
 
-	  You will need a recent binutils (2.22 or later) with
-	  elf32_x86_64 support enabled to compile a kernel with this
-	  option set.
-
 config COMPAT_32
 	def_bool y
 	depends on IA32_EMULATION || X86_32
@@ -2882,7 +2878,7 @@ config COMPAT_32
 
 config COMPAT
 	def_bool y
-	depends on IA32_EMULATION || X86_X32
+	depends on IA32_EMULATION || X86_X32_ABI
 
 if COMPAT
 config COMPAT_FOR_U64_ALIGNMENT
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index f29c2c9..63d50f6 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -152,22 +152,6 @@ else
         KBUILD_CFLAGS += -mcmodel=kernel
 endif
 
-ifdef CONFIG_X86_X32
-	x32_ld_ok := $(call try-run,\
-			/bin/echo -e '1: .quad 1b' | \
-			$(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
-			$(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMP.o" && \
-			$(LD) -m elf32_x86_64 "$$TMP.o" -o "$$TMP",y,n)
-        ifeq ($(x32_ld_ok),y)
-                CONFIG_X86_X32_ABI := y
-                KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
-                KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
-        else
-                $(warning CONFIG_X86_X32 enabled but no binutils support)
-        endif
-endif
-export CONFIG_X86_X32_ABI
-
 #
 # If the function graph tracer is used with mcount instead of fentry,
 # '-maccumulate-outgoing-args' is needed to prevent a GCC bug
diff --git a/arch/x86/entry/syscalls/Makefile b/arch/x86/entry/syscalls/Makefile
index 5b3efed..7f3886e 100644
--- a/arch/x86/entry/syscalls/Makefile
+++ b/arch/x86/entry/syscalls/Makefile
@@ -67,7 +67,7 @@ uapisyshdr-y			+= unistd_32.h unistd_64.h unistd_x32.h
 syshdr-y			+= syscalls_32.h
 syshdr-$(CONFIG_X86_64)		+= unistd_32_ia32.h unistd_64_x32.h
 syshdr-$(CONFIG_X86_64)		+= syscalls_64.h
-syshdr-$(CONFIG_X86_X32)	+= syscalls_x32.h
+syshdr-$(CONFIG_X86_X32_ABI)	+= syscalls_x32.h
 syshdr-$(CONFIG_XEN)		+= xen-hypercalls.h
 
 uapisyshdr-y	:= $(addprefix $(uapi)/, $(uapisyshdr-y))
diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index 6a2827d..59358d1 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -159,7 +159,7 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
 #endif /* CONFIG_IA32_EMULATION */
 
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /*
  * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware
  * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common
@@ -177,12 +177,12 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
 
 #define __X32_COMPAT_SYS_NI(name)					\
 	__SYS_NI(x64, compat_sys_##name)
-#else /* CONFIG_X86_X32 */
+#else /* CONFIG_X86_X32_ABI */
 #define __X32_COMPAT_SYS_STUB0(name)
 #define __X32_COMPAT_SYS_STUBx(x, name, ...)
 #define __X32_COMPAT_COND_SYSCALL(name)
 #define __X32_COMPAT_SYS_NI(name)
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 
 #ifdef CONFIG_COMPAT
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index 98aa103..2963a2f 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -37,7 +37,7 @@ struct vdso_image {
 extern const struct vdso_image vdso_image_64;
 #endif
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 extern const struct vdso_image vdso_image_x32;
 #endif
 
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 3402ede..e459253 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -681,7 +681,7 @@ void set_personality_64bit(void)
 
 static void __set_personality_x32(void)
 {
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	if (current->mm)
 		current->mm->context.flags = 0;
 
diff --git a/fs/fuse/ioctl.c b/fs/fuse/ioctl.c
index df58966..33cde4b 100644
--- a/fs/fuse/ioctl.c
+++ b/fs/fuse/ioctl.c
@@ -170,7 +170,7 @@ long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 #else
 	if (flags & FUSE_IOCTL_COMPAT) {
 		inarg.flags |= FUSE_IOCTL_32BIT;
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 		if (in_x32_syscall())
 			inarg.flags |= FUSE_IOCTL_COMPAT_X32;
 #endif
diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index 004ed2a..ca25ed8 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -217,7 +217,7 @@ xfs_compat_ioc_fsbulkstat(
 	inumbers_fmt_pf		inumbers_func = xfs_fsinumbers_fmt_compat;
 	bulkstat_one_fmt_pf	bs_one_func = xfs_fsbulkstat_one_fmt_compat;
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	if (in_x32_syscall()) {
 		/*
 		 * ... but on x32 the input xfs_fsop_bulkreq has pointers
diff --git a/sound/core/control_compat.c b/sound/core/control_compat.c
index edff063..d8a86d1 100644
--- a/sound/core/control_compat.c
+++ b/sound/core/control_compat.c
@@ -150,7 +150,7 @@ struct snd_ctl_elem_value32 {
         unsigned char reserved[128];
 };
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /* x32 has a different alignment for 64bit values from ia32 */
 struct snd_ctl_elem_value_x32 {
 	struct snd_ctl_elem_id id;
@@ -162,7 +162,7 @@ struct snd_ctl_elem_value_x32 {
 	} value;
 	unsigned char reserved[128];
 };
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 /* get the value type and count of the control */
 static int get_ctl_type(struct snd_card *card, struct snd_ctl_elem_id *id,
@@ -347,7 +347,7 @@ static int snd_ctl_elem_write_user_compat(struct snd_ctl_file *file,
 	return ctl_elem_write_user(file, data32, &data32->value);
 }
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 static int snd_ctl_elem_read_user_x32(struct snd_card *card,
 				      struct snd_ctl_elem_value_x32 __user *data32)
 {
@@ -359,7 +359,7 @@ static int snd_ctl_elem_write_user_x32(struct snd_ctl_file *file,
 {
 	return ctl_elem_write_user(file, data32, &data32->value);
 }
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 /* add or replace a user control */
 static int snd_ctl_elem_add_compat(struct snd_ctl_file *file,
@@ -418,10 +418,10 @@ enum {
 	SNDRV_CTL_IOCTL_ELEM_WRITE32 = _IOWR('U', 0x13, struct snd_ctl_elem_value32),
 	SNDRV_CTL_IOCTL_ELEM_ADD32 = _IOWR('U', 0x17, struct snd_ctl_elem_info32),
 	SNDRV_CTL_IOCTL_ELEM_REPLACE32 = _IOWR('U', 0x18, struct snd_ctl_elem_info32),
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	SNDRV_CTL_IOCTL_ELEM_READ_X32 = _IOWR('U', 0x12, struct snd_ctl_elem_value_x32),
 	SNDRV_CTL_IOCTL_ELEM_WRITE_X32 = _IOWR('U', 0x13, struct snd_ctl_elem_value_x32),
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 };
 
 static inline long snd_ctl_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg)
@@ -460,12 +460,12 @@ static inline long snd_ctl_ioctl_compat(struct file *file, unsigned int cmd, uns
 		return snd_ctl_elem_add_compat(ctl, argp, 0);
 	case SNDRV_CTL_IOCTL_ELEM_REPLACE32:
 		return snd_ctl_elem_add_compat(ctl, argp, 1);
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	case SNDRV_CTL_IOCTL_ELEM_READ_X32:
 		return snd_ctl_elem_read_user_x32(ctl->card, argp);
 	case SNDRV_CTL_IOCTL_ELEM_WRITE_X32:
 		return snd_ctl_elem_write_user_x32(ctl, argp);
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 	}
 
 	down_read(&snd_ioctl_rwsem);
diff --git a/sound/core/pcm_compat.c b/sound/core/pcm_compat.c
index e4e1768..917c5b4 100644
--- a/sound/core/pcm_compat.c
+++ b/sound/core/pcm_compat.c
@@ -147,13 +147,13 @@ static int snd_pcm_ioctl_channel_info_compat(struct snd_pcm_substream *substream
 	return err;
 }
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /* X32 ABI has the same struct as x86-64 for snd_pcm_channel_info */
 static int snd_pcm_channel_info_user(struct snd_pcm_substream *substream,
 				     struct snd_pcm_channel_info __user *src);
 #define snd_pcm_ioctl_channel_info_x32(s, p)	\
 	snd_pcm_channel_info_user(s, p)
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 struct compat_snd_pcm_status64 {
 	snd_pcm_state_t state;
@@ -375,7 +375,7 @@ static int snd_pcm_ioctl_xfern_compat(struct snd_pcm_substream *substream,
 	return err;
 }
 
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 /* X32 ABI has 64bit timespec and 64bit alignment */
 struct snd_pcm_mmap_status_x32 {
 	snd_pcm_state_t state;
@@ -468,7 +468,7 @@ static int snd_pcm_ioctl_sync_ptr_x32(struct snd_pcm_substream *substream,
 
 	return 0;
 }
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 
 #ifdef __BIG_ENDIAN
 typedef char __pad_before_u32[4];
@@ -560,10 +560,10 @@ enum {
 	SNDRV_PCM_IOCTL_READN_FRAMES32 = _IOR('A', 0x53, struct snd_xfern32),
 	SNDRV_PCM_IOCTL_STATUS_COMPAT64 = _IOR('A', 0x20, struct compat_snd_pcm_status64),
 	SNDRV_PCM_IOCTL_STATUS_EXT_COMPAT64 = _IOWR('A', 0x24, struct compat_snd_pcm_status64),
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	SNDRV_PCM_IOCTL_CHANNEL_INFO_X32 = _IOR('A', 0x32, struct snd_pcm_channel_info),
 	SNDRV_PCM_IOCTL_SYNC_PTR_X32 = _IOWR('A', 0x23, struct snd_pcm_sync_ptr_x32),
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 };
 
 static long snd_pcm_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg)
@@ -607,10 +607,10 @@ static long snd_pcm_ioctl_compat(struct file *file, unsigned int cmd, unsigned l
 	case __SNDRV_PCM_IOCTL_SYNC_PTR32:
 		return snd_pcm_common_ioctl(file, substream, cmd, argp);
 	case __SNDRV_PCM_IOCTL_SYNC_PTR64:
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 		if (in_x32_syscall())
 			return snd_pcm_ioctl_sync_ptr_x32(substream, argp);
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 		return snd_pcm_ioctl_sync_ptr_buggy(substream, argp);
 	case SNDRV_PCM_IOCTL_HW_REFINE32:
 		return snd_pcm_ioctl_hw_params_compat(substream, 1, argp);
@@ -642,10 +642,10 @@ static long snd_pcm_ioctl_compat(struct file *file, unsigned int cmd, unsigned l
 		return snd_pcm_status_user_compat64(substream, argp, false);
 	case SNDRV_PCM_IOCTL_STATUS_EXT_COMPAT64:
 		return snd_pcm_status_user_compat64(substream, argp, true);
-#ifdef CONFIG_X86_X32
+#ifdef CONFIG_X86_X32_ABI
 	case SNDRV_PCM_IOCTL_CHANNEL_INFO_X32:
 		return snd_pcm_ioctl_channel_info_x32(substream, argp);
-#endif /* CONFIG_X86_X32 */
+#endif /* CONFIG_X86_X32_ABI */
 	}
 
 	return -ENOIOCTLCMD;

^ permalink raw reply related	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2022-03-15 10:43 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-14 19:48 [PATCH 0/2] x86: Avoid CONFIG_X86_X32_ABI=y with llvm-objcopy Nathan Chancellor
2022-03-14 19:48 ` Nathan Chancellor
2022-03-14 19:48 ` [PATCH 1/2] x86: Remove toolchain check for X32 ABI capability Nathan Chancellor
2022-03-14 19:48   ` Nathan Chancellor
2022-03-15 10:43   ` [tip: x86/core] " tip-bot2 for Masahiro Yamada
2022-03-14 19:48 ` [PATCH 2/2] x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy Nathan Chancellor
2022-03-14 19:48   ` Nathan Chancellor
2022-03-15 10:43   ` [tip: x86/core] " tip-bot2 for Nathan Chancellor
2022-03-14 20:13 ` [PATCH 0/2] x86: Avoid " Peter Zijlstra
2022-03-14 20:13   ` Peter Zijlstra

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