mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
80 lines
2.2 KiB
80 lines
2.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
#include <linux/compat.h> |
|
#include <linux/errno.h> |
|
#include <linux/kernel.h> |
|
#include <linux/perf_event.h> |
|
#include <linux/bug.h> |
|
#include <linux/sched/task_stack.h> |
|
|
|
#include <asm/perf_regs.h> |
|
#include <asm/ptrace.h> |
|
|
|
u64 perf_reg_value(struct pt_regs *regs, int idx) |
|
{ |
|
if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_MAX)) |
|
return 0; |
|
|
|
/* |
|
* Our handling of compat tasks (PERF_SAMPLE_REGS_ABI_32) is weird, but |
|
* we're stuck with it for ABI compatibility reasons. |
|
* |
|
* For a 32-bit consumer inspecting a 32-bit task, then it will look at |
|
* the first 16 registers (see arch/arm/include/uapi/asm/perf_regs.h). |
|
* These correspond directly to a prefix of the registers saved in our |
|
* 'struct pt_regs', with the exception of the PC, so we copy that down |
|
* (x15 corresponds to SP_hyp in the architecture). |
|
* |
|
* So far, so good. |
|
* |
|
* The oddity arises when a 64-bit consumer looks at a 32-bit task and |
|
* asks for registers beyond PERF_REG_ARM_MAX. In this case, we return |
|
* SP_usr, LR_usr and PC in the positions where the AArch64 SP, LR and |
|
* PC registers would normally live. The initial idea was to allow a |
|
* 64-bit unwinder to unwind a 32-bit task and, although it's not clear |
|
* how well that works in practice, somebody might be relying on it. |
|
* |
|
* At the time we make a sample, we don't know whether the consumer is |
|
* 32-bit or 64-bit, so we have to cater for both possibilities. |
|
*/ |
|
if (compat_user_mode(regs)) { |
|
if ((u32)idx == PERF_REG_ARM64_SP) |
|
return regs->compat_sp; |
|
if ((u32)idx == PERF_REG_ARM64_LR) |
|
return regs->compat_lr; |
|
if (idx == 15) |
|
return regs->pc; |
|
} |
|
|
|
if ((u32)idx == PERF_REG_ARM64_SP) |
|
return regs->sp; |
|
|
|
if ((u32)idx == PERF_REG_ARM64_PC) |
|
return regs->pc; |
|
|
|
return regs->regs[idx]; |
|
} |
|
|
|
#define REG_RESERVED (~((1ULL << PERF_REG_ARM64_MAX) - 1)) |
|
|
|
int perf_reg_validate(u64 mask) |
|
{ |
|
if (!mask || mask & REG_RESERVED) |
|
return -EINVAL; |
|
|
|
return 0; |
|
} |
|
|
|
u64 perf_reg_abi(struct task_struct *task) |
|
{ |
|
if (is_compat_thread(task_thread_info(task))) |
|
return PERF_SAMPLE_REGS_ABI_32; |
|
else |
|
return PERF_SAMPLE_REGS_ABI_64; |
|
} |
|
|
|
void perf_get_regs_user(struct perf_regs *regs_user, |
|
struct pt_regs *regs) |
|
{ |
|
regs_user->regs = task_pt_regs(current); |
|
regs_user->abi = perf_reg_abi(current); |
|
}
|
|
|