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MIPS: KASLR: Correct valid bits in apply_r_mips_26_rel()

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Apply_r_mips_26_rel() relocates instructions like j, jal and etc. These
instructions consist of 6bits function field and 26bits address field.
The value of target_addr as follows,
=================================================================
|     high 4bits           |            low 28bits              |
=================================================================
|the high 4bits of this PC | the low 26bits of instructions << 2|
=================================================================
Thus, loc_orig and log_new both need high 4bits rather than high 6bits.

Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This commit is contained in:
Jinyang He 2020-11-25 18:07:18 +08:00 committed by Thomas Bogendoerfer
parent 91c7a7e065
commit 74a2810b7c
1 changed files with 2 additions and 2 deletions
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4
arch/mips/kernel/relocate.c
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@ -95,7 +95,7 @@ static int __init apply_r_mips_26_rel(u32 *loc_orig, u32 *loc_new, long offset)
/* Original target address */
target_addr <<= 2;
target_addr += (unsigned long)loc_orig & ~0x03ffffff;
target_addr += (unsigned long)loc_orig & 0xf0000000;
/* Get the new target address */
target_addr += offset;
@ -105,7 +105,7 @@ static int __init apply_r_mips_26_rel(u32 *loc_orig, u32 *loc_new, long offset)
return -ENOEXEC;
}
target_addr -= (unsigned long)loc_new & ~0x03ffffff;
target_addr -= (unsigned long)loc_new & 0xf0000000;
target_addr >>= 2;
*loc_new = (*loc_new & ~0x03ffffff) | (target_addr & 0x03ffffff);