1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/compat.h>
3 #include <linux/errno.h>
4 #include <linux/kernel.h>
5 #include <linux/perf_event.h>
7 #include <linux/sched/task_stack.h>
9 #include <asm/perf_regs.h>
10 #include <asm/ptrace.h>
12 static u64
perf_ext_regs_value(int idx
)
15 case PERF_REG_ARM64_VG
:
16 if (WARN_ON_ONCE(!system_supports_sve()))
20 * Vector granule is current length in bits of SVE registers
23 return (task_get_sve_vl(current
) * 8) / 64;
30 u64
perf_reg_value(struct pt_regs
*regs
, int idx
)
32 if (WARN_ON_ONCE((u32
)idx
>= PERF_REG_ARM64_EXTENDED_MAX
))
36 * Our handling of compat tasks (PERF_SAMPLE_REGS_ABI_32) is weird, but
37 * we're stuck with it for ABI compatibility reasons.
39 * For a 32-bit consumer inspecting a 32-bit task, then it will look at
40 * the first 16 registers (see arch/arm/include/uapi/asm/perf_regs.h).
41 * These correspond directly to a prefix of the registers saved in our
42 * 'struct pt_regs', with the exception of the PC, so we copy that down
43 * (x15 corresponds to SP_hyp in the architecture).
47 * The oddity arises when a 64-bit consumer looks at a 32-bit task and
48 * asks for registers beyond PERF_REG_ARM_MAX. In this case, we return
49 * SP_usr, LR_usr and PC in the positions where the AArch64 SP, LR and
50 * PC registers would normally live. The initial idea was to allow a
51 * 64-bit unwinder to unwind a 32-bit task and, although it's not clear
52 * how well that works in practice, somebody might be relying on it.
54 * At the time we make a sample, we don't know whether the consumer is
55 * 32-bit or 64-bit, so we have to cater for both possibilities.
57 if (compat_user_mode(regs
)) {
58 if ((u32
)idx
== PERF_REG_ARM64_SP
)
59 return regs
->compat_sp
;
60 if ((u32
)idx
== PERF_REG_ARM64_LR
)
61 return regs
->compat_lr
;
66 if ((u32
)idx
== PERF_REG_ARM64_SP
)
69 if ((u32
)idx
== PERF_REG_ARM64_PC
)
72 if ((u32
)idx
>= PERF_REG_ARM64_MAX
)
73 return perf_ext_regs_value(idx
);
75 return regs
->regs
[idx
];
78 #define REG_RESERVED (~((1ULL << PERF_REG_ARM64_MAX) - 1))
80 int perf_reg_validate(u64 mask
)
82 u64 reserved_mask
= REG_RESERVED
;
84 if (system_supports_sve())
85 reserved_mask
&= ~(1ULL << PERF_REG_ARM64_VG
);
87 if (!mask
|| mask
& reserved_mask
)
93 u64
perf_reg_abi(struct task_struct
*task
)
95 if (is_compat_thread(task_thread_info(task
)))
96 return PERF_SAMPLE_REGS_ABI_32
;
98 return PERF_SAMPLE_REGS_ABI_64
;
101 void perf_get_regs_user(struct perf_regs
*regs_user
,
102 struct pt_regs
*regs
)
104 regs_user
->regs
= task_pt_regs(current
);
105 regs_user
->abi
= perf_reg_abi(current
);