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linux-next/include/linux/arm-smccc.h
Marc Zyngier 755a8bf557 arm/arm64: smccc-1.1: Handle function result as parameters
If someone has the silly idea to write something along those lines:

	extern u64 foo(void);

	void bar(struct arm_smccc_res *res)
	{
		arm_smccc_1_1_smc(0xbad, foo(), res);
	}

they are in for a surprise, as this gets compiled as:

	0000000000000588 <bar>:
	 588:   a9be7bfd        stp     x29, x30, [sp, #-32]!
	 58c:   910003fd        mov     x29, sp
	 590:   f9000bf3        str     x19, [sp, #16]
	 594:   aa0003f3        mov     x19, x0
	 598:   aa1e03e0        mov     x0, x30
	 59c:   94000000        bl      0 <_mcount>
	 5a0:   94000000        bl      0 <foo>
	 5a4:   aa0003e1        mov     x1, x0
	 5a8:   d4000003        smc     #0x0
	 5ac:   b4000073        cbz     x19, 5b8 <bar+0x30>
	 5b0:   a9000660        stp     x0, x1, [x19]
	 5b4:   a9010e62        stp     x2, x3, [x19, #16]
	 5b8:   f9400bf3        ldr     x19, [sp, #16]
	 5bc:   a8c27bfd        ldp     x29, x30, [sp], #32
	 5c0:   d65f03c0        ret
	 5c4:   d503201f        nop

The call to foo "overwrites" the x0 register for the return value,
and we end up calling the wrong secure service.

A solution is to evaluate all the parameters before assigning
anything to specific registers, leading to the expected result:

	0000000000000588 <bar>:
	 588:   a9be7bfd        stp     x29, x30, [sp, #-32]!
	 58c:   910003fd        mov     x29, sp
	 590:   f9000bf3        str     x19, [sp, #16]
	 594:   aa0003f3        mov     x19, x0
	 598:   aa1e03e0        mov     x0, x30
	 59c:   94000000        bl      0 <_mcount>
	 5a0:   94000000        bl      0 <foo>
	 5a4:   aa0003e1        mov     x1, x0
	 5a8:   d28175a0        mov     x0, #0xbad
	 5ac:   d4000003        smc     #0x0
	 5b0:   b4000073        cbz     x19, 5bc <bar+0x34>
	 5b4:   a9000660        stp     x0, x1, [x19]
	 5b8:   a9010e62        stp     x2, x3, [x19, #16]
	 5bc:   f9400bf3        ldr     x19, [sp, #16]
	 5c0:   a8c27bfd        ldp     x29, x30, [sp], #32
	 5c4:   d65f03c0        ret

Reported-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-08-30 14:18:03 +01:00

316 lines
10 KiB
C

/*
* Copyright (c) 2015, Linaro Limited
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#ifndef __LINUX_ARM_SMCCC_H
#define __LINUX_ARM_SMCCC_H
#include <uapi/linux/const.h>
/*
* This file provides common defines for ARM SMC Calling Convention as
* specified in
* http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html
*/
#define ARM_SMCCC_STD_CALL _AC(0,U)
#define ARM_SMCCC_FAST_CALL _AC(1,U)
#define ARM_SMCCC_TYPE_SHIFT 31
#define ARM_SMCCC_SMC_32 0
#define ARM_SMCCC_SMC_64 1
#define ARM_SMCCC_CALL_CONV_SHIFT 30
#define ARM_SMCCC_OWNER_MASK 0x3F
#define ARM_SMCCC_OWNER_SHIFT 24
#define ARM_SMCCC_FUNC_MASK 0xFFFF
#define ARM_SMCCC_IS_FAST_CALL(smc_val) \
((smc_val) & (ARM_SMCCC_FAST_CALL << ARM_SMCCC_TYPE_SHIFT))
#define ARM_SMCCC_IS_64(smc_val) \
((smc_val) & (ARM_SMCCC_SMC_64 << ARM_SMCCC_CALL_CONV_SHIFT))
#define ARM_SMCCC_FUNC_NUM(smc_val) ((smc_val) & ARM_SMCCC_FUNC_MASK)
#define ARM_SMCCC_OWNER_NUM(smc_val) \
(((smc_val) >> ARM_SMCCC_OWNER_SHIFT) & ARM_SMCCC_OWNER_MASK)
#define ARM_SMCCC_CALL_VAL(type, calling_convention, owner, func_num) \
(((type) << ARM_SMCCC_TYPE_SHIFT) | \
((calling_convention) << ARM_SMCCC_CALL_CONV_SHIFT) | \
(((owner) & ARM_SMCCC_OWNER_MASK) << ARM_SMCCC_OWNER_SHIFT) | \
((func_num) & ARM_SMCCC_FUNC_MASK))
#define ARM_SMCCC_OWNER_ARCH 0
#define ARM_SMCCC_OWNER_CPU 1
#define ARM_SMCCC_OWNER_SIP 2
#define ARM_SMCCC_OWNER_OEM 3
#define ARM_SMCCC_OWNER_STANDARD 4
#define ARM_SMCCC_OWNER_TRUSTED_APP 48
#define ARM_SMCCC_OWNER_TRUSTED_APP_END 49
#define ARM_SMCCC_OWNER_TRUSTED_OS 50
#define ARM_SMCCC_OWNER_TRUSTED_OS_END 63
#define ARM_SMCCC_QUIRK_NONE 0
#define ARM_SMCCC_QUIRK_QCOM_A6 1 /* Save/restore register a6 */
#define ARM_SMCCC_VERSION_1_0 0x10000
#define ARM_SMCCC_VERSION_1_1 0x10001
#define ARM_SMCCC_VERSION_FUNC_ID \
ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
ARM_SMCCC_SMC_32, \
0, 0)
#define ARM_SMCCC_ARCH_FEATURES_FUNC_ID \
ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
ARM_SMCCC_SMC_32, \
0, 1)
#define ARM_SMCCC_ARCH_WORKAROUND_1 \
ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
ARM_SMCCC_SMC_32, \
0, 0x8000)
#define ARM_SMCCC_ARCH_WORKAROUND_2 \
ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \
ARM_SMCCC_SMC_32, \
0, 0x7fff)
#ifndef __ASSEMBLY__
#include <linux/linkage.h>
#include <linux/types.h>
/**
* struct arm_smccc_res - Result from SMC/HVC call
* @a0-a3 result values from registers 0 to 3
*/
struct arm_smccc_res {
unsigned long a0;
unsigned long a1;
unsigned long a2;
unsigned long a3;
};
/**
* struct arm_smccc_quirk - Contains quirk information
* @id: quirk identification
* @state: quirk specific information
* @a6: Qualcomm quirk entry for returning post-smc call contents of a6
*/
struct arm_smccc_quirk {
int id;
union {
unsigned long a6;
} state;
};
/**
* __arm_smccc_smc() - make SMC calls
* @a0-a7: arguments passed in registers 0 to 7
* @res: result values from registers 0 to 3
* @quirk: points to an arm_smccc_quirk, or NULL when no quirks are required.
*
* This function is used to make SMC calls following SMC Calling Convention.
* The content of the supplied param are copied to registers 0 to 7 prior
* to the SMC instruction. The return values are updated with the content
* from register 0 to 3 on return from the SMC instruction. An optional
* quirk structure provides vendor specific behavior.
*/
asmlinkage 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);
/**
* __arm_smccc_hvc() - make HVC calls
* @a0-a7: arguments passed in registers 0 to 7
* @res: result values from registers 0 to 3
* @quirk: points to an arm_smccc_quirk, or NULL when no quirks are required.
*
* This function is used to make HVC calls following SMC Calling
* Convention. The content of the supplied param are copied to registers 0
* to 7 prior to the HVC instruction. The return values are updated with
* the content from register 0 to 3 on return from the HVC instruction. An
* optional quirk structure provides vendor specific behavior.
*/
asmlinkage 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);
#define arm_smccc_smc(...) __arm_smccc_smc(__VA_ARGS__, NULL)
#define arm_smccc_smc_quirk(...) __arm_smccc_smc(__VA_ARGS__)
#define arm_smccc_hvc(...) __arm_smccc_hvc(__VA_ARGS__, NULL)
#define arm_smccc_hvc_quirk(...) __arm_smccc_hvc(__VA_ARGS__)
/* SMCCC v1.1 implementation madness follows */
#ifdef CONFIG_ARM64
#define SMCCC_SMC_INST "smc #0"
#define SMCCC_HVC_INST "hvc #0"
#elif defined(CONFIG_ARM)
#include <asm/opcodes-sec.h>
#include <asm/opcodes-virt.h>
#define SMCCC_SMC_INST __SMC(0)
#define SMCCC_HVC_INST __HVC(0)
#endif
#define ___count_args(_0, _1, _2, _3, _4, _5, _6, _7, _8, x, ...) x
#define __count_args(...) \
___count_args(__VA_ARGS__, 7, 6, 5, 4, 3, 2, 1, 0)
#define __constraint_write_0 \
"+r" (r0), "=&r" (r1), "=&r" (r2), "=&r" (r3)
#define __constraint_write_1 \
"+r" (r0), "+r" (r1), "=&r" (r2), "=&r" (r3)
#define __constraint_write_2 \
"+r" (r0), "+r" (r1), "+r" (r2), "=&r" (r3)
#define __constraint_write_3 \
"+r" (r0), "+r" (r1), "+r" (r2), "+r" (r3)
#define __constraint_write_4 __constraint_write_3
#define __constraint_write_5 __constraint_write_4
#define __constraint_write_6 __constraint_write_5
#define __constraint_write_7 __constraint_write_6
#define __constraint_read_0
#define __constraint_read_1
#define __constraint_read_2
#define __constraint_read_3
#define __constraint_read_4 "r" (r4)
#define __constraint_read_5 __constraint_read_4, "r" (r5)
#define __constraint_read_6 __constraint_read_5, "r" (r6)
#define __constraint_read_7 __constraint_read_6, "r" (r7)
#define __declare_arg_0(a0, res) \
struct arm_smccc_res *___res = res; \
register unsigned long r0 asm("r0") = (u32)a0; \
register unsigned long r1 asm("r1"); \
register unsigned long r2 asm("r2"); \
register unsigned long r3 asm("r3")
#define __declare_arg_1(a0, a1, res) \
typeof(a1) __a1 = a1; \
struct arm_smccc_res *___res = res; \
register unsigned long r0 asm("r0") = (u32)a0; \
register unsigned long r1 asm("r1") = __a1; \
register unsigned long r2 asm("r2"); \
register unsigned long r3 asm("r3")
#define __declare_arg_2(a0, a1, a2, res) \
typeof(a1) __a1 = a1; \
typeof(a2) __a2 = a2; \
struct arm_smccc_res *___res = res; \
register unsigned long r0 asm("r0") = (u32)a0; \
register unsigned long r1 asm("r1") = __a1; \
register unsigned long r2 asm("r2") = __a2; \
register unsigned long r3 asm("r3")
#define __declare_arg_3(a0, a1, a2, a3, res) \
typeof(a1) __a1 = a1; \
typeof(a2) __a2 = a2; \
typeof(a3) __a3 = a3; \
struct arm_smccc_res *___res = res; \
register unsigned long r0 asm("r0") = (u32)a0; \
register unsigned long r1 asm("r1") = __a1; \
register unsigned long r2 asm("r2") = __a2; \
register unsigned long r3 asm("r3") = __a3
#define __declare_arg_4(a0, a1, a2, a3, a4, res) \
typeof(a4) __a4 = a4; \
__declare_arg_3(a0, a1, a2, a3, res); \
register unsigned long r4 asm("r4") = __a4
#define __declare_arg_5(a0, a1, a2, a3, a4, a5, res) \
typeof(a5) __a5 = a5; \
__declare_arg_4(a0, a1, a2, a3, a4, res); \
register unsigned long r5 asm("r5") = __a5
#define __declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res) \
typeof(a6) __a6 = a6; \
__declare_arg_5(a0, a1, a2, a3, a4, a5, res); \
register unsigned long r6 asm("r6") = __a6
#define __declare_arg_7(a0, a1, a2, a3, a4, a5, a6, a7, res) \
typeof(a7) __a7 = a7; \
__declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res); \
register unsigned long r7 asm("r7") = __a7
#define ___declare_args(count, ...) __declare_arg_ ## count(__VA_ARGS__)
#define __declare_args(count, ...) ___declare_args(count, __VA_ARGS__)
#define ___constraints(count) \
: __constraint_write_ ## count \
: __constraint_read_ ## count \
: "memory"
#define __constraints(count) ___constraints(count)
/*
* We have an output list that is not necessarily used, and GCC feels
* entitled to optimise the whole sequence away. "volatile" is what
* makes it stick.
*/
#define __arm_smccc_1_1(inst, ...) \
do { \
__declare_args(__count_args(__VA_ARGS__), __VA_ARGS__); \
asm volatile(inst "\n" \
__constraints(__count_args(__VA_ARGS__))); \
if (___res) \
*___res = (typeof(*___res)){r0, r1, r2, r3}; \
} while (0)
/*
* arm_smccc_1_1_smc() - make an SMCCC v1.1 compliant SMC call
*
* This is a variadic macro taking one to eight source arguments, and
* an optional return structure.
*
* @a0-a7: arguments passed in registers 0 to 7
* @res: result values from registers 0 to 3
*
* This macro is used to make SMC calls following SMC Calling Convention v1.1.
* The content of the supplied param are copied to registers 0 to 7 prior
* to the SMC instruction. The return values are updated with the content
* from register 0 to 3 on return from the SMC instruction if not NULL.
*/
#define arm_smccc_1_1_smc(...) __arm_smccc_1_1(SMCCC_SMC_INST, __VA_ARGS__)
/*
* arm_smccc_1_1_hvc() - make an SMCCC v1.1 compliant HVC call
*
* This is a variadic macro taking one to eight source arguments, and
* an optional return structure.
*
* @a0-a7: arguments passed in registers 0 to 7
* @res: result values from registers 0 to 3
*
* This macro is used to make HVC calls following SMC Calling Convention v1.1.
* The content of the supplied param are copied to registers 0 to 7 prior
* to the HVC instruction. The return values are updated with the content
* from register 0 to 3 on return from the HVC instruction if not NULL.
*/
#define arm_smccc_1_1_hvc(...) __arm_smccc_1_1(SMCCC_HVC_INST, __VA_ARGS__)
/* Return codes defined in ARM DEN 0070A */
#define SMCCC_RET_SUCCESS 0
#define SMCCC_RET_NOT_SUPPORTED -1
#define SMCCC_RET_NOT_REQUIRED -2
#endif /*__ASSEMBLY__*/
#endif /*__LINUX_ARM_SMCCC_H*/