linux-kernel - [PATCH 4.14 30/41] powerpc/lib/feature-fixups: use raw_patch

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Date:   Thu, 18 Oct 2018 19:54:45 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Christophe Leroy <christophe.leroy@....fr>,
        Michael Ellerman <mpe@...erman.id.au>,
        David Gounaris <david.gounaris@...inera.com>
Subject: [PATCH 4.14 30/41] powerpc/lib/feature-fixups: use raw_patch_instruction()

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Christophe Leroy <christophe.leroy@....fr>

commit 8183d99f4a22c2abbc543847a588df3666ef0c0c upstream.

feature fixups need to use patch_instruction() early in the boot,
even before the code is relocated to its final address, requiring
patch_instruction() to use PTRRELOC() in order to address data.

But feature fixups applies on code before it is set to read only,
even for modules. Therefore, feature fixups can use
raw_patch_instruction() instead.

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Reported-by: David Gounaris <david.gounaris@...inera.com>
Tested-by: David Gounaris <david.gounaris@...inera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/powerpc/include/asm/code-patching.h |    1 +
 arch/powerpc/lib/code-patching.c         |    4 ++--
 arch/powerpc/lib/feature-fixups.c        |    8 ++++----
 3 files changed, 7 insertions(+), 6 deletions(-)

--- a/arch/powerpc/include/asm/code-patching.h
+++ b/arch/powerpc/include/asm/code-patching.h
@@ -31,6 +31,7 @@ unsigned int create_cond_branch(const un
 				unsigned long target, int flags);
 int patch_branch(unsigned int *addr, unsigned long target, int flags);
 int patch_instruction(unsigned int *addr, unsigned int instr);
+int raw_patch_instruction(unsigned int *addr, unsigned int instr);
 
 int instr_is_relative_branch(unsigned int instr);
 int instr_is_relative_link_branch(unsigned int instr);
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -39,7 +39,7 @@ static int __patch_instruction(unsigned
 	return 0;
 }
 
-static int raw_patch_instruction(unsigned int *addr, unsigned int instr)
+int raw_patch_instruction(unsigned int *addr, unsigned int instr)
 {
 	return __patch_instruction(addr, instr, addr);
 }
@@ -156,7 +156,7 @@ static int do_patch_instruction(unsigned
 	 * when text_poke_area is not ready, but we still need
 	 * to allow patching. We just do the plain old patching
 	 */
-	if (!this_cpu_read(*PTRRELOC(&text_poke_area)))
+	if (!this_cpu_read(text_poke_area))
 		return raw_patch_instruction(addr, instr);
 
 	local_irq_save(flags);
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -63,7 +63,7 @@ static int patch_alt_instruction(unsigne
 		}
 	}
 
-	patch_instruction(dest, instr);
+	raw_patch_instruction(dest, instr);
 
 	return 0;
 }
@@ -92,7 +92,7 @@ static int patch_feature_section(unsigne
 	}
 
 	for (; dest < end; dest++)
-		patch_instruction(dest, PPC_INST_NOP);
+		raw_patch_instruction(dest, PPC_INST_NOP);
 
 	return 0;
 }
@@ -292,7 +292,7 @@ void do_lwsync_fixups(unsigned long valu
 
 	for (; start < end; start++) {
 		dest = (void *)start + *start;
-		patch_instruction(dest, PPC_INST_LWSYNC);
+		raw_patch_instruction(dest, PPC_INST_LWSYNC);
 	}
 }
 
@@ -310,7 +310,7 @@ static void do_final_fixups(void)
 	length = (__end_interrupts - _stext) / sizeof(int);
 
 	while (length--) {
-		patch_instruction(dest, *src);
+		raw_patch_instruction(dest, *src);
 		src++;
 		dest++;
 	}