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From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	naveen.n.rao@linux.vnet.ibm.com
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 02/25] powerpc/ftrace: Remove redundant create_branch() calls
Date: Sat,  7 May 2022 08:46:04 +0200	[thread overview]
Message-ID: <aa45fbad0b4b7493080835d8276c0cb4ce146503.1651905939.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1651905939.git.christophe.leroy@csgroup.eu>

Since commit d5937db114e4 ("powerpc/code-patching: Fix patch_branch()
return on out-of-range failure") patch_branch() fails with -ERANGE
when trying to branch out of range.

No need to perform the test twice. Remove redundant create_branch()
calls.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/trace/ftrace.c | 20 --------------------
 1 file changed, 20 deletions(-)

diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index 7a266fd469b7..3ce3697e8a7c 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -301,7 +301,6 @@ static int setup_mcount_compiler_tramp(unsigned long tramp)
 	int i;
 	ppc_inst_t op;
 	unsigned long ptr;
-	ppc_inst_t instr;
 	static unsigned long ftrace_plt_tramps[NUM_FTRACE_TRAMPS];
 
 	/* Is this a known long jump tramp? */
@@ -344,12 +343,6 @@ static int setup_mcount_compiler_tramp(unsigned long tramp)
 #else
 	ptr = ppc_global_function_entry((void *)ftrace_caller);
 #endif
-	if (create_branch(&instr, (void *)tramp, ptr, 0)) {
-		pr_debug("%ps is not reachable from existing mcount tramp\n",
-				(void *)ptr);
-		return -1;
-	}
-
 	if (patch_branch((u32 *)tramp, ptr, 0)) {
 		pr_debug("REL24 out of range!\n");
 		return -1;
@@ -490,7 +483,6 @@ static int
 __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 {
 	ppc_inst_t op[2];
-	ppc_inst_t instr;
 	void *ip = (void *)rec->ip;
 	unsigned long entry, ptr, tramp;
 	struct module *mod = rec->arch.mod;
@@ -539,12 +531,6 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 		return -EINVAL;
 	}
 
-	/* Ensure branch is within 24 bits */
-	if (create_branch(&instr, ip, tramp, BRANCH_SET_LINK)) {
-		pr_err("Branch out of range\n");
-		return -EINVAL;
-	}
-
 	if (patch_branch(ip, tramp, BRANCH_SET_LINK)) {
 		pr_err("REL24 out of range!\n");
 		return -EINVAL;
@@ -770,12 +756,6 @@ __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 		return -EINVAL;
 	}
 
-	/* Ensure branch is within 24 bits */
-	if (create_branch(&op, (u32 *)ip, tramp, BRANCH_SET_LINK)) {
-		pr_err("Branch out of range\n");
-		return -EINVAL;
-	}
-
 	if (patch_branch((u32 *)ip, tramp, BRANCH_SET_LINK)) {
 		pr_err("REL24 out of range!\n");
 		return -EINVAL;
-- 
2.35.1


  parent reply	other threads:[~2022-05-07  6:47 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-07  6:46 [PATCH v2 00/25] powerpc: ftrace optimisation and cleanup and more [v2] Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 01/25] powerpc/ftrace: Refactor prepare_ftrace_return() Christophe Leroy
2022-05-07  6:46 ` Christophe Leroy [this message]
2022-05-07  6:46 ` [PATCH v2 03/25] powerpc/code-patching: Inline is_offset_in_{cond}_branch_range() Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 04/25] powerpc/ftrace: Use is_offset_in_branch_range() Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 05/25] powerpc/code-patching: Inline create_branch() Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 06/25] powerpc/ftrace: Inline ftrace_modify_code() Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 07/25] powerpc/ftrace: Use patch_instruction() return directly Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 08/25] powerpc: Add CONFIG_PPC64_ELF_ABI_V1 and CONFIG_PPC64_ELF_ABI_V2 Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 09/25] powerpc: Replace PPC64_ELF_ABI_v{1/2} by CONFIG_PPC64_ELF_ABI_V{1/2} Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 10/25] powerpc: Finalise cleanup around ABI use Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 11/25] powerpc/ftrace: Make __ftrace_make_{nop/call}() common to PPC32 and PPC64 Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 12/25] powerpc/ftrace: Don't include ftrace.o for CONFIG_FTRACE_SYSCALLS Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 13/25] powerpc/ftrace: Use CONFIG_FUNCTION_TRACER instead of CONFIG_DYNAMIC_FTRACE Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 14/25] powerpc/ftrace: Remove ftrace_plt_tramps[] Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 15/25] powerpc/ftrace: Use BRANCH_SET_LINK instead of value 1 Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 16/25] powerpc/ftrace: Use PPC_RAW_xxx() macros instead of opencoding Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 17/25] powerpc/ftrace: Use size macro " Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 18/25] powerpc/ftrace: Simplify expected_nop_sequence() Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 19/25] powerpc/ftrace: Minimise number of #ifdefs Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 20/25] powerpc/inst: Add __copy_inst_from_kernel_nofault() Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 21/25] powerpc/ftrace: Don't use copy_from_kernel_nofault() in module_trampoline_target() Christophe Leroy
2022-05-07 11:29   ` kernel test robot
2022-05-07  6:46 ` [PATCH v2 22/25] powerpc/inst: Remove PPC_INST_BRANCH Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 23/25] powerpc/modules: Use PPC_LI macros instead of opencoding Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 24/25] powerpc/inst: Remove PPC_INST_BL Christophe Leroy
2022-05-07  6:46 ` [PATCH v2 25/25] powerpc/opcodes: Remove unused PPC_INST_XXX macros Christophe Leroy

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