[RFC PATCH 6/9] arm64: smccc: create proper stack frames for HVC/SMC calls
From: Ard Biesheuvel <ardb@kernel.org>
Date: 2021-10-13 15:26:43
Also in:
linux-hardening
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Create proper stack frames using the provided macros for HVC/SMC calling helpers that use the stack. This adds the PAC return address signing when enabled, and ensures that the unwinder can deal with occurrences of these routines appearing on the call stack. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- arch/arm64/kernel/smccc-call.S | 40 +++++++++----------- 1 file changed, 17 insertions(+), 23 deletions(-)
diff --git a/arch/arm64/kernel/smccc-call.S b/arch/arm64/kernel/smccc-call.S
index 487381164ff6..b1864880159a 100644
--- a/arch/arm64/kernel/smccc-call.S
+++ b/arch/arm64/kernel/smccc-call.S@@ -32,8 +32,7 @@ SYM_FUNC_END(__arm_smccc_sve_check) EXPORT_SYMBOL(__arm_smccc_sve_check) .macro SMCCC instr - stp x29, x30, [sp, #-16]! - mov x29, sp + frame_push 0 alternative_if ARM64_SVE bl __arm_smccc_sve_check alternative_else_nop_endif
@@ -47,7 +46,7 @@ alternative_else_nop_endif cmp x9, #ARM_SMCCC_QUIRK_QCOM_A6 b.ne 1f str x6, [x4, ARM_SMCCC_QUIRK_STATE_OFFS] -1: ldp x29, x30, [sp], #16 +1: frame_pop ret .endm
@@ -74,11 +73,10 @@ SYM_FUNC_END(__arm_smccc_hvc) EXPORT_SYMBOL(__arm_smccc_hvc) .macro SMCCC_1_2 instr - /* Save `res` and free a GPR that won't be clobbered */ - stp x1, x19, [sp, #-16]! + frame_push 2 - /* Ensure `args` won't be clobbered while loading regs in next step */ - mov x19, x0 + mov x19, x0 // preserve args + mov x20, x1 // preserve res /* Load the registers x0 - x17 from the struct arm_smccc_1_2_regs */ ldp x0, x1, [x19, #ARM_SMCCC_1_2_REGS_X0_OFFS]
@@ -93,24 +91,20 @@ EXPORT_SYMBOL(__arm_smccc_hvc) \instr #0 - /* Load the `res` from the stack */ - ldr x19, [sp] - /* Store the registers x0 - x17 into the result structure */ - stp x0, x1, [x19, #ARM_SMCCC_1_2_REGS_X0_OFFS] - stp x2, x3, [x19, #ARM_SMCCC_1_2_REGS_X2_OFFS] - stp x4, x5, [x19, #ARM_SMCCC_1_2_REGS_X4_OFFS] - stp x6, x7, [x19, #ARM_SMCCC_1_2_REGS_X6_OFFS] - stp x8, x9, [x19, #ARM_SMCCC_1_2_REGS_X8_OFFS] - stp x10, x11, [x19, #ARM_SMCCC_1_2_REGS_X10_OFFS] - stp x12, x13, [x19, #ARM_SMCCC_1_2_REGS_X12_OFFS] - stp x14, x15, [x19, #ARM_SMCCC_1_2_REGS_X14_OFFS] - stp x16, x17, [x19, #ARM_SMCCC_1_2_REGS_X16_OFFS] - - /* Restore original x19 */ - ldp xzr, x19, [sp], #16 + stp x0, x1, [x20, #ARM_SMCCC_1_2_REGS_X0_OFFS] + stp x2, x3, [x20, #ARM_SMCCC_1_2_REGS_X2_OFFS] + stp x4, x5, [x20, #ARM_SMCCC_1_2_REGS_X4_OFFS] + stp x6, x7, [x20, #ARM_SMCCC_1_2_REGS_X6_OFFS] + stp x8, x9, [x20, #ARM_SMCCC_1_2_REGS_X8_OFFS] + stp x10, x11, [x20, #ARM_SMCCC_1_2_REGS_X10_OFFS] + stp x12, x13, [x20, #ARM_SMCCC_1_2_REGS_X12_OFFS] + stp x14, x15, [x20, #ARM_SMCCC_1_2_REGS_X14_OFFS] + stp x16, x17, [x20, #ARM_SMCCC_1_2_REGS_X16_OFFS] + + frame_pop ret -.endm + .endm /* * void arm_smccc_1_2_hvc(const struct arm_smccc_1_2_regs *args,
--
2.30.2
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