From: Andy Lutomirski luto@kernel.org
[ Upstream commit 700d3a5a664df267f01ec8887fd2d8ff98f67e7f ]
Revert
45e29d119e99 ("x86/syscalls: Make __X32_SYSCALL_BIT be unsigned long")
and add a comment to discourage someone else from making the same mistake again.
It turns out that some user code fails to compile if __X32_SYSCALL_BIT is unsigned long. See, for example [1] below.
[ bp: Massage and do the same thing in the respective tools/ header. ]
Fixes: 45e29d119e99 ("x86/syscalls: Make __X32_SYSCALL_BIT be unsigned long") Reported-by: Thorsten Glaser t.glaser@tarent.de Signed-off-by: Andy Lutomirski luto@kernel.org Signed-off-by: Borislav Petkov bp@suse.de Cc: stable@kernel.org Link: [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=954294 Link: https://lkml.kernel.org/r/92e55442b744a5951fdc9cfee10badd0a5f7f828.158898389... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/include/uapi/asm/unistd.h | 11 +++++++++-- tools/arch/x86/include/uapi/asm/unistd.h | 2 +- 2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/uapi/asm/unistd.h b/arch/x86/include/uapi/asm/unistd.h index 196fdd02b8b1..be5e2e747f50 100644 --- a/arch/x86/include/uapi/asm/unistd.h +++ b/arch/x86/include/uapi/asm/unistd.h @@ -2,8 +2,15 @@ #ifndef _UAPI_ASM_X86_UNISTD_H #define _UAPI_ASM_X86_UNISTD_H
-/* x32 syscall flag bit */ -#define __X32_SYSCALL_BIT 0x40000000UL +/* + * x32 syscall flag bit. Some user programs expect syscall NR macros + * and __X32_SYSCALL_BIT to have type int, even though syscall numbers + * are, for practical purposes, unsigned long. + * + * Fortunately, expressions like (nr & ~__X32_SYSCALL_BIT) do the right + * thing regardless. + */ +#define __X32_SYSCALL_BIT 0x40000000
#ifndef __KERNEL__ # ifdef __i386__ diff --git a/tools/arch/x86/include/uapi/asm/unistd.h b/tools/arch/x86/include/uapi/asm/unistd.h index 196fdd02b8b1..30d7d04d72d6 100644 --- a/tools/arch/x86/include/uapi/asm/unistd.h +++ b/tools/arch/x86/include/uapi/asm/unistd.h @@ -3,7 +3,7 @@ #define _UAPI_ASM_X86_UNISTD_H
/* x32 syscall flag bit */ -#define __X32_SYSCALL_BIT 0x40000000UL +#define __X32_SYSCALL_BIT 0x40000000
#ifndef __KERNEL__ # ifdef __i386__