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authorAndy Lutomirski <luto@kernel.org>2020-05-08 17:25:32 -0700
committerBorislav Petkov <bp@suse.de>2020-05-26 16:42:43 +0200
commit700d3a5a664df267f01ec8887fd2d8ff98f67e7f (patch)
tree59478760a27451a973433c3f412d79a69ae070e6 /arch
parent9cb1fd0efd195590b828b9b865421ad345a4a145 (diff)
x86/syscalls: Revert "x86/syscalls: Make __X32_SYSCALL_BIT be unsigned long"
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/92e55442b744a5951fdc9cfee10badd0a5f7f828.1588983892.git.luto@kernel.org
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/uapi/asm/unistd.h11
1 files changed, 9 insertions, 2 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__