diff options
| author | J. Tang <tang@jtang.org> | 2017-02-09 21:54:13 -0500 |
|---|---|---|
| committer | Bin Meng <bmeng.cn@gmail.com> | 2017-02-21 14:53:29 +0800 |
| commit | 3c03f4928e96dce4c6cd14fb630dacad13a141ae (patch) | |
| tree | 7f6c83e07b2d23b3491ea989b92f95726b349a21 /arch/x86 | |
| parent | 66c246cce7c66019a93ff7105157c3e2126dd277 (diff) | |
x86: Force 32-bit jumps in interrupt handlers
Depending upon the compiler used, IRQ entries could vary in sizes. With
GCC 5.x, the code generator will use short jumps for some IRQ entries
but near jumps for others. For example, GCC 5.4.0 generates the
following:
$ objdump -d interrupt.o
<snip>
00000207 <irq_18>:
207: 6a 12 push $0x12
209: eb 85 jmp 190 <irq_common_entry>
0000020b <irq_19>:
20b: 6a 13 push $0x13
20d: eb 81 jmp 190 <irq_common_entry>
0000020f <irq_20>:
20f: 6a 14 push $0x14
211: e9 7a ff ff ff jmp 190 <irq_common_entry>
00000216 <irq_21>:
216: 6a 15 push $0x15
218: e9 73 ff ff ff jmp 190 <irq_common_entry>
This causes a problem in cpu_init_interrupts(), because the IDT setup
assumed same sizes for all IRQ entries. GCC 4.x always generated 32-bit
jumps, so this previously was not a problem.
The fix is to force 32-bit near jumps for all entries within the
inline assembly. This works for GCC 5.x, and 4.x was already using
that form of jumping.
Signed-off-by: Jason Tang <tang@jtang.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/cpu/i386/interrupt.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/cpu/i386/interrupt.c b/arch/x86/cpu/i386/interrupt.c index a05830326b..ba576fef3c 100644 --- a/arch/x86/cpu/i386/interrupt.c +++ b/arch/x86/cpu/i386/interrupt.c @@ -28,7 +28,7 @@ DECLARE_GLOBAL_DATA_PTR; ".type irq_"#x", @function\n" \ "irq_"#x":\n" \ "pushl $"#x"\n" \ - "jmp irq_common_entry\n" + "jmp.d32 irq_common_entry\n" static char *exceptions[] = { "Divide Error", |