From 35df0155e68a1fb20646f34247f19131170693bd Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Mon, 21 Mar 2022 21:40:49 -0700 Subject: [PATCH] Revert "powerpc: Add rethook support" This reverts commit 02752bd99dc2daae05c12f7063bf0632e22b4c1c. Signed-off-by: Alexei Starovoitov --- arch/powerpc/Kconfig | 1 - arch/powerpc/kernel/Makefile | 1 - arch/powerpc/kernel/rethook.c | 72 ----------------------------------- 3 files changed, 74 deletions(-) delete mode 100644 arch/powerpc/kernel/rethook.c diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 5feaa241fb56..b779603978e1 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -229,7 +229,6 @@ config PPC select HAVE_PERF_EVENTS_NMI if PPC64 select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP - select HAVE_RETHOOK if KPROBES select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_RELIABLE_STACKTRACE select HAVE_RSEQ diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index feb24ea83ca6..4d7829399570 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -115,7 +115,6 @@ obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_OPTPROBES) += optprobes.o optprobes_head.o obj-$(CONFIG_KPROBES_ON_FTRACE) += kprobes-ftrace.o -obj-$(CONFIG_RETHOOK) += rethook.o obj-$(CONFIG_UPROBES) += uprobes.o obj-$(CONFIG_PPC_UDBG_16550) += legacy_serial.o udbg_16550.o obj-$(CONFIG_SWIOTLB) += dma-swiotlb.o diff --git a/arch/powerpc/kernel/rethook.c b/arch/powerpc/kernel/rethook.c deleted file mode 100644 index a8a128748efa..000000000000 --- a/arch/powerpc/kernel/rethook.c +++ /dev/null @@ -1,72 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* - * PowerPC implementation of rethook. This depends on kprobes. - */ - -#include -#include - -/* - * Function return trampoline: - * - init_kprobes() establishes a probepoint here - * - When the probed function returns, this probe - * causes the handlers to fire - */ -asm(".global arch_rethook_trampoline\n" - ".type arch_rethook_trampoline, @function\n" - "arch_rethook_trampoline:\n" - "nop\n" - "blr\n" - ".size arch_rethook_trampoline, .-arch_rethook_trampoline\n"); - -/* - * Called when the probe at kretprobe trampoline is hit - */ -static int trampoline_rethook_handler(struct kprobe *p, struct pt_regs *regs) -{ - unsigned long orig_ret_address; - - orig_ret_address = rethook_trampoline_handler(regs, 0); - /* - * We get here through one of two paths: - * 1. by taking a trap -> kprobe_handler() -> here - * 2. by optprobe branch -> optimized_callback() -> opt_pre_handler() -> here - * - * When going back through (1), we need regs->nip to be setup properly - * as it is used to determine the return address from the trap. - * For (2), since nip is not honoured with optprobes, we instead setup - * the link register properly so that the subsequent 'blr' in - * __kretprobe_trampoline jumps back to the right instruction. - * - * For nip, we should set the address to the previous instruction since - * we end up emulating it in kprobe_handler(), which increments the nip - * again. - */ - regs_set_return_ip(regs, orig_ret_address - 4); - regs->link = orig_ret_address; - - return 0; -} -NOKPROBE_SYMBOL(trampoline_rethook_handler); - -void arch_rethook_prepare(struct rethook_node *rh, struct pt_regs *regs, bool mcount) -{ - rh->ret_addr = regs->link; - rh->frame = 0; - - /* Replace the return addr with trampoline addr */ - regs->link = (unsigned long)arch_rethook_trampoline; -} -NOKPROBE_SYMBOL(arch_prepare_kretprobe); - -static struct kprobe trampoline_p = { - .addr = (kprobe_opcode_t *) &arch_rethook_trampoline, - .pre_handler = trampoline_rethook_handler -}; - -static int init_arch_rethook(void) -{ - return register_kprobe(&trampoline_p); -} - -core_initcall(init_arch_rethook); -- 2.34.1