Commit baa763b5 authored by Suzuki K Poulose's avatar Suzuki K Poulose Committed by Will Deacon

arm64: alternative: Disallow patching instructions using literals

The alternative code patching doesn't check if the replaced instruction
uses a pc relative literal. This could cause silent corruption in the
instruction stream as the instruction will be executed from a different
address than what it was compiled for. Catch all such cases.

Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Suggested-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent c47a1900
......@@ -79,6 +79,12 @@ static u32 get_alt_insn(struct alt_instr *alt, u32 *insnptr, u32 *altinsnptr)
offset = target - (unsigned long)insnptr;
insn = aarch64_set_branch_offset(insn, offset);
}
} else if (aarch64_insn_uses_literal(insn)) {
/*
* Disallow patching unhandled instructions using PC relative
* literal addresses
*/
BUG();
}
return insn;
......
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