linux/arch/arm64/kernel/smccc-call.S
Jean-Philippe Brucker a7c3acca53 arm64: smccc: Save lr before calling __arm_smccc_sve_check()
Commit cfa7ff959a ("arm64: smccc: Support SMCCC v1.3 SVE register
saving hint") added a call to __arm_smccc_sve_check() which clobbers the
lr (register x30), causing __arm_smccc_hvc() to return to itself and
crash. Save lr on the stack before calling __arm_smccc_sve_check(). Save
the frame pointer (x29) to complete the frame record, and adjust the
offsets used to access stack parameters.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Fixes: cfa7ff959a ("arm64: smccc: Support SMCCC v1.3 SVE register saving hint")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20210721071834.69130-1-jean-philippe@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>
2021-07-21 11:23:25 +01:00

132 lines
3.8 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (c) 2015, Linaro Limited
*/
#include <linux/linkage.h>
#include <linux/arm-smccc.h>
#include <asm/asm-offsets.h>
#include <asm/assembler.h>
#include <asm/thread_info.h>
/*
* If we have SMCCC v1.3 and (as is likely) no SVE state in
* the registers then set the SMCCC hint bit to say there's no
* need to preserve it. Do this by directly adjusting the SMCCC
* function value which is already stored in x0 ready to be called.
*/
SYM_FUNC_START(__arm_smccc_sve_check)
ldr_l x16, smccc_has_sve_hint
cbz x16, 2f
get_current_task x16
ldr x16, [x16, #TSK_TI_FLAGS]
tbnz x16, #TIF_FOREIGN_FPSTATE, 1f // Any live FP state?
tbnz x16, #TIF_SVE, 2f // Does that state include SVE?
1: orr x0, x0, ARM_SMCCC_1_3_SVE_HINT
2: ret
SYM_FUNC_END(__arm_smccc_sve_check)
EXPORT_SYMBOL(__arm_smccc_sve_check)
.macro SMCCC instr
stp x29, x30, [sp, #-16]!
mov x29, sp
alternative_if ARM64_SVE
bl __arm_smccc_sve_check
alternative_else_nop_endif
\instr #0
ldr x4, [sp, #16]
stp x0, x1, [x4, #ARM_SMCCC_RES_X0_OFFS]
stp x2, x3, [x4, #ARM_SMCCC_RES_X2_OFFS]
ldr x4, [sp, #24]
cbz x4, 1f /* no quirk structure */
ldr x9, [x4, #ARM_SMCCC_QUIRK_ID_OFFS]
cmp x9, #ARM_SMCCC_QUIRK_QCOM_A6
b.ne 1f
str x6, [x4, ARM_SMCCC_QUIRK_STATE_OFFS]
1: ldp x29, x30, [sp], #16
ret
.endm
/*
* void arm_smccc_smc(unsigned long a0, unsigned long a1, unsigned long a2,
* unsigned long a3, unsigned long a4, unsigned long a5,
* unsigned long a6, unsigned long a7, struct arm_smccc_res *res,
* struct arm_smccc_quirk *quirk)
*/
SYM_FUNC_START(__arm_smccc_smc)
SMCCC smc
SYM_FUNC_END(__arm_smccc_smc)
EXPORT_SYMBOL(__arm_smccc_smc)
/*
* void arm_smccc_hvc(unsigned long a0, unsigned long a1, unsigned long a2,
* unsigned long a3, unsigned long a4, unsigned long a5,
* unsigned long a6, unsigned long a7, struct arm_smccc_res *res,
* struct arm_smccc_quirk *quirk)
*/
SYM_FUNC_START(__arm_smccc_hvc)
SMCCC hvc
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]!
/* Ensure `args` won't be clobbered while loading regs in next step */
mov x19, x0
/* Load the registers x0 - x17 from the struct arm_smccc_1_2_regs */
ldp x0, x1, [x19, #ARM_SMCCC_1_2_REGS_X0_OFFS]
ldp x2, x3, [x19, #ARM_SMCCC_1_2_REGS_X2_OFFS]
ldp x4, x5, [x19, #ARM_SMCCC_1_2_REGS_X4_OFFS]
ldp x6, x7, [x19, #ARM_SMCCC_1_2_REGS_X6_OFFS]
ldp x8, x9, [x19, #ARM_SMCCC_1_2_REGS_X8_OFFS]
ldp x10, x11, [x19, #ARM_SMCCC_1_2_REGS_X10_OFFS]
ldp x12, x13, [x19, #ARM_SMCCC_1_2_REGS_X12_OFFS]
ldp x14, x15, [x19, #ARM_SMCCC_1_2_REGS_X14_OFFS]
ldp x16, x17, [x19, #ARM_SMCCC_1_2_REGS_X16_OFFS]
\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
ret
.endm
/*
* void arm_smccc_1_2_hvc(const struct arm_smccc_1_2_regs *args,
* struct arm_smccc_1_2_regs *res);
*/
SYM_FUNC_START(arm_smccc_1_2_hvc)
SMCCC_1_2 hvc
SYM_FUNC_END(arm_smccc_1_2_hvc)
EXPORT_SYMBOL(arm_smccc_1_2_hvc)
/*
* void arm_smccc_1_2_smc(const struct arm_smccc_1_2_regs *args,
* struct arm_smccc_1_2_regs *res);
*/
SYM_FUNC_START(arm_smccc_1_2_smc)
SMCCC_1_2 smc
SYM_FUNC_END(arm_smccc_1_2_smc)
EXPORT_SYMBOL(arm_smccc_1_2_smc)