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e30e8d46cf
Due to inconsistencies in the way we manipulate compat GPRs, we have a few issues today: * For audit and tracing, where error codes are handled as a (native) long, negative error codes are expected to be sign-extended to the native 64-bits, or they may fail to be matched correctly. Thus a syscall which fails with an error may erroneously be identified as failing. * For ptrace, *all* compat return values should be sign-extended for consistency with 32-bit arm, but we currently only do this for negative return codes. * As we may transiently set the upper 32 bits of some compat GPRs while in the kernel, these can be sampled by perf, which is somewhat confusing. This means that where a syscall returns a pointer above 2G, this will be sign-extended, but will not be mistaken for an error as error codes are constrained to the inclusive range [-4096, -1] where no user pointer can exist. To fix all of these, we must consistently use helpers to get/set the compat GPRs, ensuring that we never write the upper 32 bits of the return code, and always sign-extend when reading the return code. This patch does so, with the following changes: * We re-organise syscall_get_return_value() to always sign-extend for compat tasks, and reimplement syscall_get_error() atop. We update syscall_trace_exit() to use syscall_get_return_value(). * We consistently use syscall_set_return_value() to set the return value, ensureing the upper 32 bits are never set unexpectedly. * As the core audit code currently uses regs_return_value() rather than syscall_get_return_value(), we special-case this for compat_user_mode(regs) such that this will do the right thing. Going forward, we should try to move the core audit code over to syscall_get_return_value(). Cc: <stable@vger.kernel.org> Reported-by: He Zhe <zhe.he@windriver.com> Reported-by: weiyuchen <weiyuchen3@huawei.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20210802104200.21390-1-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
394 lines
10 KiB
C
394 lines
10 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Based on arch/arm/include/asm/ptrace.h
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*
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* Copyright (C) 1996-2003 Russell King
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* Copyright (C) 2012 ARM Ltd.
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*/
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#ifndef __ASM_PTRACE_H
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#define __ASM_PTRACE_H
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#include <asm/cpufeature.h>
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#include <uapi/asm/ptrace.h>
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/* Current Exception Level values, as contained in CurrentEL */
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#define CurrentEL_EL1 (1 << 2)
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#define CurrentEL_EL2 (2 << 2)
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#define INIT_PSTATE_EL1 \
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(PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT | PSR_MODE_EL1h)
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#define INIT_PSTATE_EL2 \
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(PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT | PSR_MODE_EL2h)
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/*
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* PMR values used to mask/unmask interrupts.
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*
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* GIC priority masking works as follows: if an IRQ's priority is a higher value
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* than the value held in PMR, that IRQ is masked. Lowering the value of PMR
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* means masking more IRQs (or at least that the same IRQs remain masked).
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*
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* To mask interrupts, we clear the most significant bit of PMR.
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*
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* Some code sections either automatically switch back to PSR.I or explicitly
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* require to not use priority masking. If bit GIC_PRIO_PSR_I_SET is included
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* in the priority mask, it indicates that PSR.I should be set and
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* interrupt disabling temporarily does not rely on IRQ priorities.
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*/
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#define GIC_PRIO_IRQON 0xe0
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#define __GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80)
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#define __GIC_PRIO_IRQOFF_NS 0xa0
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#define GIC_PRIO_PSR_I_SET (1 << 4)
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#define GIC_PRIO_IRQOFF \
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({ \
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extern struct static_key_false gic_nonsecure_priorities;\
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u8 __prio = __GIC_PRIO_IRQOFF; \
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\
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if (static_branch_unlikely(&gic_nonsecure_priorities)) \
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__prio = __GIC_PRIO_IRQOFF_NS; \
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\
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__prio; \
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})
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/* Additional SPSR bits not exposed in the UABI */
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#define PSR_MODE_THREAD_BIT (1 << 0)
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#define PSR_IL_BIT (1 << 20)
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/* AArch32-specific ptrace requests */
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#define COMPAT_PTRACE_GETREGS 12
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#define COMPAT_PTRACE_SETREGS 13
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#define COMPAT_PTRACE_GET_THREAD_AREA 22
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#define COMPAT_PTRACE_SET_SYSCALL 23
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#define COMPAT_PTRACE_GETVFPREGS 27
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#define COMPAT_PTRACE_SETVFPREGS 28
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#define COMPAT_PTRACE_GETHBPREGS 29
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#define COMPAT_PTRACE_SETHBPREGS 30
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/* SPSR_ELx bits for exceptions taken from AArch32 */
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#define PSR_AA32_MODE_MASK 0x0000001f
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#define PSR_AA32_MODE_USR 0x00000010
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#define PSR_AA32_MODE_FIQ 0x00000011
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#define PSR_AA32_MODE_IRQ 0x00000012
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#define PSR_AA32_MODE_SVC 0x00000013
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#define PSR_AA32_MODE_ABT 0x00000017
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#define PSR_AA32_MODE_HYP 0x0000001a
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#define PSR_AA32_MODE_UND 0x0000001b
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#define PSR_AA32_MODE_SYS 0x0000001f
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#define PSR_AA32_T_BIT 0x00000020
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#define PSR_AA32_F_BIT 0x00000040
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#define PSR_AA32_I_BIT 0x00000080
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#define PSR_AA32_A_BIT 0x00000100
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#define PSR_AA32_E_BIT 0x00000200
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#define PSR_AA32_PAN_BIT 0x00400000
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#define PSR_AA32_SSBS_BIT 0x00800000
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#define PSR_AA32_DIT_BIT 0x01000000
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#define PSR_AA32_Q_BIT 0x08000000
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#define PSR_AA32_V_BIT 0x10000000
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#define PSR_AA32_C_BIT 0x20000000
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#define PSR_AA32_Z_BIT 0x40000000
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#define PSR_AA32_N_BIT 0x80000000
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#define PSR_AA32_IT_MASK 0x0600fc00 /* If-Then execution state mask */
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#define PSR_AA32_GE_MASK 0x000f0000
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#ifdef CONFIG_CPU_BIG_ENDIAN
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#define PSR_AA32_ENDSTATE PSR_AA32_E_BIT
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#else
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#define PSR_AA32_ENDSTATE 0
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#endif
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/* AArch32 CPSR bits, as seen in AArch32 */
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#define COMPAT_PSR_DIT_BIT 0x00200000
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/*
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* These are 'magic' values for PTRACE_PEEKUSR that return info about where a
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* process is located in memory.
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*/
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#define COMPAT_PT_TEXT_ADDR 0x10000
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#define COMPAT_PT_DATA_ADDR 0x10004
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#define COMPAT_PT_TEXT_END_ADDR 0x10008
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/*
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* If pt_regs.syscallno == NO_SYSCALL, then the thread is not executing
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* a syscall -- i.e., its most recent entry into the kernel from
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* userspace was not via SVC, or otherwise a tracer cancelled the syscall.
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*
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* This must have the value -1, for ABI compatibility with ptrace etc.
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*/
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#define NO_SYSCALL (-1)
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#ifndef __ASSEMBLY__
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#include <linux/bug.h>
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#include <linux/types.h>
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/* sizeof(struct user) for AArch32 */
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#define COMPAT_USER_SZ 296
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/* Architecturally defined mapping between AArch32 and AArch64 registers */
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#define compat_usr(x) regs[(x)]
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#define compat_fp regs[11]
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#define compat_sp regs[13]
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#define compat_lr regs[14]
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#define compat_sp_hyp regs[15]
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#define compat_lr_irq regs[16]
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#define compat_sp_irq regs[17]
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#define compat_lr_svc regs[18]
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#define compat_sp_svc regs[19]
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#define compat_lr_abt regs[20]
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#define compat_sp_abt regs[21]
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#define compat_lr_und regs[22]
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#define compat_sp_und regs[23]
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#define compat_r8_fiq regs[24]
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#define compat_r9_fiq regs[25]
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#define compat_r10_fiq regs[26]
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#define compat_r11_fiq regs[27]
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#define compat_r12_fiq regs[28]
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#define compat_sp_fiq regs[29]
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#define compat_lr_fiq regs[30]
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static inline unsigned long compat_psr_to_pstate(const unsigned long psr)
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{
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unsigned long pstate;
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pstate = psr & ~COMPAT_PSR_DIT_BIT;
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if (psr & COMPAT_PSR_DIT_BIT)
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pstate |= PSR_AA32_DIT_BIT;
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return pstate;
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}
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static inline unsigned long pstate_to_compat_psr(const unsigned long pstate)
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{
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unsigned long psr;
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psr = pstate & ~PSR_AA32_DIT_BIT;
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if (pstate & PSR_AA32_DIT_BIT)
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psr |= COMPAT_PSR_DIT_BIT;
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return psr;
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}
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/*
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* This struct defines the way the registers are stored on the stack during an
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* exception. Note that sizeof(struct pt_regs) has to be a multiple of 16 (for
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* stack alignment). struct user_pt_regs must form a prefix of struct pt_regs.
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*/
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struct pt_regs {
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union {
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struct user_pt_regs user_regs;
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struct {
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u64 regs[31];
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u64 sp;
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u64 pc;
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u64 pstate;
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};
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};
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u64 orig_x0;
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#ifdef __AARCH64EB__
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u32 unused2;
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s32 syscallno;
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#else
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s32 syscallno;
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u32 unused2;
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#endif
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u64 sdei_ttbr1;
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/* Only valid when ARM64_HAS_IRQ_PRIO_MASKING is enabled. */
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u64 pmr_save;
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u64 stackframe[2];
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/* Only valid for some EL1 exceptions. */
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u64 lockdep_hardirqs;
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u64 exit_rcu;
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};
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static inline bool in_syscall(struct pt_regs const *regs)
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{
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return regs->syscallno != NO_SYSCALL;
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}
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static inline void forget_syscall(struct pt_regs *regs)
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{
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regs->syscallno = NO_SYSCALL;
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}
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#define MAX_REG_OFFSET offsetof(struct pt_regs, pstate)
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#define arch_has_single_step() (1)
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#ifdef CONFIG_COMPAT
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#define compat_thumb_mode(regs) \
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(((regs)->pstate & PSR_AA32_T_BIT))
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#else
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#define compat_thumb_mode(regs) (0)
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#endif
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#define user_mode(regs) \
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(((regs)->pstate & PSR_MODE_MASK) == PSR_MODE_EL0t)
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#define compat_user_mode(regs) \
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(((regs)->pstate & (PSR_MODE32_BIT | PSR_MODE_MASK)) == \
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(PSR_MODE32_BIT | PSR_MODE_EL0t))
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#define processor_mode(regs) \
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((regs)->pstate & PSR_MODE_MASK)
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#define irqs_priority_unmasked(regs) \
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(system_uses_irq_prio_masking() ? \
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(regs)->pmr_save == GIC_PRIO_IRQON : \
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true)
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#define interrupts_enabled(regs) \
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(!((regs)->pstate & PSR_I_BIT) && irqs_priority_unmasked(regs))
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#define fast_interrupts_enabled(regs) \
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(!((regs)->pstate & PSR_F_BIT))
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static inline unsigned long user_stack_pointer(struct pt_regs *regs)
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{
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if (compat_user_mode(regs))
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return regs->compat_sp;
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return regs->sp;
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}
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extern int regs_query_register_offset(const char *name);
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extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
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unsigned int n);
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/**
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* regs_get_register() - get register value from its offset
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* @regs: pt_regs from which register value is gotten
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* @offset: offset of the register.
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*
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* regs_get_register returns the value of a register whose offset from @regs.
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* The @offset is the offset of the register in struct pt_regs.
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* If @offset is bigger than MAX_REG_OFFSET, this returns 0.
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*/
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static inline u64 regs_get_register(struct pt_regs *regs, unsigned int offset)
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{
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u64 val = 0;
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WARN_ON(offset & 7);
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offset >>= 3;
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switch (offset) {
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case 0 ... 30:
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val = regs->regs[offset];
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break;
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case offsetof(struct pt_regs, sp) >> 3:
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val = regs->sp;
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break;
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case offsetof(struct pt_regs, pc) >> 3:
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val = regs->pc;
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break;
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case offsetof(struct pt_regs, pstate) >> 3:
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val = regs->pstate;
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break;
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default:
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val = 0;
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}
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return val;
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}
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/*
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* Read a register given an architectural register index r.
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* This handles the common case where 31 means XZR, not SP.
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*/
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static inline unsigned long pt_regs_read_reg(const struct pt_regs *regs, int r)
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{
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return (r == 31) ? 0 : regs->regs[r];
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}
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/*
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* Write a register given an architectural register index r.
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* This handles the common case where 31 means XZR, not SP.
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*/
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static inline void pt_regs_write_reg(struct pt_regs *regs, int r,
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unsigned long val)
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{
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if (r != 31)
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regs->regs[r] = val;
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}
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/* Valid only for Kernel mode traps. */
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static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
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{
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return regs->sp;
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}
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static inline unsigned long regs_return_value(struct pt_regs *regs)
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{
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unsigned long val = regs->regs[0];
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/*
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* Audit currently uses regs_return_value() instead of
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* syscall_get_return_value(). Apply the same sign-extension here until
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* audit is updated to use syscall_get_return_value().
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*/
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if (compat_user_mode(regs))
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val = sign_extend64(val, 31);
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return val;
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}
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static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
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{
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regs->regs[0] = rc;
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}
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/**
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* regs_get_kernel_argument() - get Nth function argument in kernel
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* @regs: pt_regs of that context
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* @n: function argument number (start from 0)
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*
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* regs_get_argument() returns @n th argument of the function call.
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*
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* Note that this chooses the most likely register mapping. In very rare
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* cases this may not return correct data, for example, if one of the
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* function parameters is 16 bytes or bigger. In such cases, we cannot
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* get access the parameter correctly and the register assignment of
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* subsequent parameters will be shifted.
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*/
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static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs,
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unsigned int n)
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{
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#define NR_REG_ARGUMENTS 8
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if (n < NR_REG_ARGUMENTS)
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return pt_regs_read_reg(regs, n);
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return 0;
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}
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/* We must avoid circular header include via sched.h */
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struct task_struct;
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int valid_user_regs(struct user_pt_regs *regs, struct task_struct *task);
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static inline unsigned long instruction_pointer(struct pt_regs *regs)
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{
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return regs->pc;
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}
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static inline void instruction_pointer_set(struct pt_regs *regs,
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unsigned long val)
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{
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regs->pc = val;
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}
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static inline unsigned long frame_pointer(struct pt_regs *regs)
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{
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return regs->regs[29];
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}
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#define procedure_link_pointer(regs) ((regs)->regs[30])
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static inline void procedure_link_pointer_set(struct pt_regs *regs,
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unsigned long val)
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{
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procedure_link_pointer(regs) = val;
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}
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extern unsigned long profile_pc(struct pt_regs *regs);
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#endif /* __ASSEMBLY__ */
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#endif
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