linux-kernel - [PATCH v2 2/5] ARM: uapi: Drop PSR

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Message-Id: <20260112-headers_install-config-leak-v2-2-4d8084444603@linutronix.de>
Date: Mon, 12 Jan 2026 08:58:30 +0100
From: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
To: Vineet Gupta <vgupta@...nel.org>, Russell King <linux@...linux.org.uk>, 
 Dinh Nguyen <dinguyen@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, 
 Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
 Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
 "H. Peter Anvin" <hpa@...or.com>
Cc: linux-snps-arc@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 linux-arm-kernel@...ts.infradead.org, Arnd Bergmann <arnd@...db.de>, 
 Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Subject: [PATCH v2 2/5] ARM: uapi: Drop PSR_ENDSTATE

The symbol PSR_ENDSTATE is pointless for userspace. Drop it from the
UAPI headers and instead inline it into the only two callers.

As as side-effect, remove a leak of an internal kconfig symbol through
the UAPI headers.

Suggested-by: Arnd Bergmann <arnd@...db.de>
Link: https://lore.kernel.org/lkml/d2ad12f2-3d65-4bef-890c-65d78a33d790@app.fastmail.com/
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
---
 arch/arm/include/asm/processor.h   | 3 ++-
 arch/arm/include/uapi/asm/ptrace.h | 9 ---------
 arch/arm/kernel/signal.c           | 3 ++-
 scripts/headers_install.sh         | 1 -
 4 files changed, 4 insertions(+), 12 deletions(-)

diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index 326864f79d18..bba83228bc22 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -73,7 +73,8 @@ static inline void arch_thread_struct_whitelist(unsigned long *offset,
 		regs->ARM_cpsr = USR26_MODE;				\
 	if (elf_hwcap & HWCAP_THUMB && pc & 1)				\
 		regs->ARM_cpsr |= PSR_T_BIT;				\
-	regs->ARM_cpsr |= PSR_ENDSTATE;					\
+	if (IS_ENABLED(CONFIG_CPU_ENDIAN_BE8))				\
+		regs->ARM_cpsr |= PSR_E_BIT;				\
 	regs->ARM_pc = pc & ~1;		/* pc */			\
 	regs->ARM_sp = sp;		/* sp */			\
 })
diff --git a/arch/arm/include/uapi/asm/ptrace.h b/arch/arm/include/uapi/asm/ptrace.h
index 8896c23ccba7..2ef917957005 100644
--- a/arch/arm/include/uapi/asm/ptrace.h
+++ b/arch/arm/include/uapi/asm/ptrace.h
@@ -102,15 +102,6 @@
 #define PSR_IT_MASK	0x0600fc00	/* If-Then execution state mask */
 #define PSR_ENDIAN_MASK	0x00000200	/* Endianness state mask */
 
-/*
- * Default endianness state
- */
-#ifdef CONFIG_CPU_ENDIAN_BE8
-#define PSR_ENDSTATE	PSR_E_BIT
-#else
-#define PSR_ENDSTATE	0
-#endif
-
 /* 
  * These are 'magic' values for PTRACE_PEEKUSR that return info about where a
  * process is located in memory.
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 79a6730fa0eb..7be9188d83d9 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -337,7 +337,8 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig,
 			return 1;
 	}
 
-	cpsr |= PSR_ENDSTATE;
+	if (IS_ENABLED(CONFIG_CPU_ENDIAN_BE8))
+		cpsr |= PSR_E_BIT;
 
 	/*
 	 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
diff --git a/scripts/headers_install.sh b/scripts/headers_install.sh
index 727f7f82c2c7..4f03521f4026 100755
--- a/scripts/headers_install.sh
+++ b/scripts/headers_install.sh
@@ -70,7 +70,6 @@ configs=$(sed -e '
 #
 # The format is <file-name>:<CONFIG-option> in each line.
 config_leak_ignores="
-arch/arm/include/uapi/asm/ptrace.h:CONFIG_CPU_ENDIAN_BE8
 arch/nios2/include/uapi/asm/swab.h:CONFIG_NIOS2_CI_SWAB_NO
 arch/nios2/include/uapi/asm/swab.h:CONFIG_NIOS2_CI_SWAB_SUPPORT
 arch/x86/include/uapi/asm/auxvec.h:CONFIG_IA32_EMULATION

-- 
2.52.0