Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) #include <linux/compat.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) #include <linux/errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) #include <linux/perf_event.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) #include <linux/bug.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) #include <linux/sched/task_stack.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) #include <asm/perf_regs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <asm/ptrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) u64 perf_reg_value(struct pt_regs *regs, int idx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) 	if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_MAX))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) 	 * Our handling of compat tasks (PERF_SAMPLE_REGS_ABI_32) is weird, but
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 	 * we're stuck with it for ABI compatibility reasons.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 	 * For a 32-bit consumer inspecting a 32-bit task, then it will look at
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 	 * the first 16 registers (see arch/arm/include/uapi/asm/perf_regs.h).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) 	 * These correspond directly to a prefix of the registers saved in our
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 	 * 'struct pt_regs', with the exception of the PC, so we copy that down
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 	 * (x15 corresponds to SP_hyp in the architecture).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 	 * So far, so good.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 	 * The oddity arises when a 64-bit consumer looks at a 32-bit task and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 	 * asks for registers beyond PERF_REG_ARM_MAX. In this case, we return
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 	 * SP_usr, LR_usr and PC in the positions where the AArch64 SP, LR and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 	 * PC registers would normally live. The initial idea was to allow a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 	 * 64-bit unwinder to unwind a 32-bit task and, although it's not clear
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 	 * how well that works in practice, somebody might be relying on it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 	 * At the time we make a sample, we don't know whether the consumer is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 	 * 32-bit or 64-bit, so we have to cater for both possibilities.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 	if (compat_user_mode(regs)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 		if ((u32)idx == PERF_REG_ARM64_SP)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 			return regs->compat_sp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 		if ((u32)idx == PERF_REG_ARM64_LR)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 			return regs->compat_lr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 		if (idx == 15)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 			return regs->pc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) 	if ((u32)idx == PERF_REG_ARM64_SP)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 		return regs->sp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) 	if ((u32)idx == PERF_REG_ARM64_PC)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 		return regs->pc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 	return regs->regs[idx];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) #define REG_RESERVED (~((1ULL << PERF_REG_ARM64_MAX) - 1))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) int perf_reg_validate(u64 mask)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) 	if (!mask || mask & REG_RESERVED)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) u64 perf_reg_abi(struct task_struct *task)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) 	if (is_compat_thread(task_thread_info(task)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) 		return PERF_SAMPLE_REGS_ABI_32;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) 		return PERF_SAMPLE_REGS_ABI_64;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) void perf_get_regs_user(struct perf_regs *regs_user,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) 			struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) 	regs_user->regs = task_pt_regs(current);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) 	regs_user->abi = perf_reg_abi(current);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) }