linux-parisc.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v2 0/6] Dynamic FTRACE for PA-RISC
@ 2019-06-04 18:34 Sven Schnelle
  2019-06-04 18:34 ` [PATCH v2 1/6] parisc: add support for patching multiple words Sven Schnelle
                   ` (5 more replies)
  0 siblings, 6 replies; 9+ messages in thread
From: Sven Schnelle @ 2019-06-04 18:34 UTC (permalink / raw)
  To: deller; +Cc: linux-parisc, Sven Schnelle

Hi List,

this series adds support for dynamic ftrace. See the commit message of
the patch for a explanation how it works. For testing, you need a patched
version of gcc because the current version has a bug which misplaces the
function label. John David Anglin can provide a patch which fixes this issue.
This issue is tracked here: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90751

Changes to v1:

- replace a few hardcoded size by sizeof()
- change len parameter of patch_text_multiple() to unsigned
- add link to gcc bugtracker

Sven Schnelle (6):
  parisc: add support for patching multiple words
  parisc: add spinlock to patch function
  parisc: add WARN_ON() to clear_fixmap
  parisc: use pr_debug() in kernel/module.c
  compiler.h: add CC_USING_PATCHABLE_FUNCTION_ENTRY
  parisc: add dynamic ftrace

 arch/parisc/Kconfig               |   2 +
 arch/parisc/Makefile              |  18 +++++
 arch/parisc/include/asm/ftrace.h  |  15 +++-
 arch/parisc/include/asm/patch.h   |   4 +-
 arch/parisc/kernel/Makefile       |   9 ++-
 arch/parisc/kernel/entry.S        |  64 +++++++++++++++
 arch/parisc/kernel/ftrace.c       | 129 +++++++++++++++++++++++++++---
 arch/parisc/kernel/module.c       |  64 +++++++++------
 arch/parisc/kernel/module.lds     |   7 ++
 arch/parisc/kernel/patch.c        |  88 ++++++++++++++++----
 arch/parisc/kernel/vmlinux.lds.S  |   2 +
 arch/parisc/mm/fixmap.c           |   7 +-
 include/asm-generic/vmlinux.lds.h |   7 ++
 include/linux/compiler_types.h    |   2 +
 14 files changed, 358 insertions(+), 60 deletions(-)
 create mode 100644 arch/parisc/kernel/module.lds

-- 
2.20.1


^ permalink raw reply	[flat|nested] 9+ messages in thread
* [PATCH v2 1/6] parisc: add support for patching multiple words
  2019-06-04 18:34 [PATCH v2 0/6] Dynamic FTRACE for PA-RISC Sven Schnelle
@ 2019-06-04 18:34 ` Sven Schnelle
  2019-06-04 19:21   ` Rolf Eike Beer
  2019-06-04 18:34 ` [PATCH v2 2/6] parisc: add spinlock to patch function Sven Schnelle
                   ` (4 subsequent siblings)
  5 siblings, 1 reply; 9+ messages in thread
From: Sven Schnelle @ 2019-06-04 18:34 UTC (permalink / raw)
  To: deller; +Cc: linux-parisc, Sven Schnelle

add patch_text_multiple() which allows to patch multiple
text words in memory. This can be used to copy functions.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 arch/parisc/include/asm/patch.h |  4 +-
 arch/parisc/kernel/patch.c      | 75 ++++++++++++++++++++++++++-------
 2 files changed, 62 insertions(+), 17 deletions(-)

diff --git a/arch/parisc/include/asm/patch.h b/arch/parisc/include/asm/patch.h
index 685b58a13968..400d84c6e504 100644
--- a/arch/parisc/include/asm/patch.h
+++ b/arch/parisc/include/asm/patch.h
@@ -4,8 +4,10 @@
 
 /* stop machine and patch kernel text */
 void patch_text(void *addr, unsigned int insn);
+void patch_text_multiple(void *addr, u32 *insn, unsigned int len);
 
 /* patch kernel text with machine already stopped (e.g. in kgdb) */
-void __patch_text(void *addr, unsigned int insn);
+void __patch_text(void *addr, u32 insn);
+void __patch_text_multiple(void *addr, u32 *insn, unsigned int len);
 
 #endif
diff --git a/arch/parisc/kernel/patch.c b/arch/parisc/kernel/patch.c
index cdcd981278b3..624de41e0524 100644
--- a/arch/parisc/kernel/patch.c
+++ b/arch/parisc/kernel/patch.c
@@ -17,15 +17,18 @@
 
 struct patch {
 	void *addr;
-	unsigned int insn;
+	u32 *insn;
+	unsigned int len;
 };
 
-static void __kprobes *patch_map(void *addr, int fixmap)
-{
+static DEFINE_RAW_SPINLOCK(patch_lock);
+
+static void __kprobes *patch_map(void *addr, int fixmap, int *need_unmap)
 	unsigned long uintaddr = (uintptr_t) addr;
 	bool module = !core_kernel_text(uintaddr);
 	struct page *page;
 
+	*need_unmap = 0;
 	if (module && IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
 		page = vmalloc_to_page(addr);
 	else if (!module && IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
@@ -33,6 +36,7 @@ static void __kprobes *patch_map(void *addr, int fixmap)
 	else
 		return addr;
 
+	*need_unmap = 1;
 	set_fixmap(fixmap, page_to_phys(page));
 
 	return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
@@ -43,34 +47,73 @@ static void __kprobes patch_unmap(int fixmap)
 	clear_fixmap(fixmap);
 }
 
-void __kprobes __patch_text(void *addr, unsigned int insn)
+void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
+{
+	unsigned long start = (unsigned long)addr;
+	unsigned long end = (unsigned long)addr + len;
+	u32 *p, *fixmap;
+	int mapped;
+
+	/* Make sure we don't have any aliases in cache */
+	flush_kernel_vmap_range(addr, len);
+	flush_icache_range(start, end);
+
+	p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &mapped);
+
+	while (len >= 4) {
+		*p++ = *insn++;
+		addr += sizeof(u32);
+		len -= sizeof(u32);
+		if (len && !((unsigned long)addr & ~PAGE_MASK)) {
+			/*
+			 * We're crossing a page boundary, so
+			 * need to remap
+			 */
+			flush_kernel_vmap_range((void *)fixmap,
+						(p-fixmap) * sizeof(*p));
+			if (mapped)
+				patch_unmap(FIX_TEXT_POKE0);
+			p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &mapped);
+		}
+	}
+
+	flush_kernel_vmap_range((void *)fixmap, (p-fixmap) * sizeof(*p));
+	if (mapped)
+		patch_unmap(FIX_TEXT_POKE0);
+	flush_icache_range(start, end);
+}
+
+void __kprobes __patch_text(void *addr, u32 insn)
 {
-	void *waddr = addr;
-	int size;
-
-	waddr = patch_map(addr, FIX_TEXT_POKE0);
-	*(u32 *)waddr = insn;
-	size = sizeof(u32);
-	flush_kernel_vmap_range(waddr, size);
-	patch_unmap(FIX_TEXT_POKE0);
-	flush_icache_range((uintptr_t)(addr),
-			   (uintptr_t)(addr) + size);
+	__patch_text_multiple(addr, &insn, sizeof(insn));
 }
 
 static int __kprobes patch_text_stop_machine(void *data)
 {
 	struct patch *patch = data;
 
-	__patch_text(patch->addr, patch->insn);
-
+	__patch_text_multiple(patch->addr, patch->insn, patch->len);
 	return 0;
 }
 
 void __kprobes patch_text(void *addr, unsigned int insn)
 {
+	struct patch patch = {
+		.addr = addr,
+		.insn = &insn,
+		.len = sizeof(insn),
+	};
+
+	stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL);
+}
+
+void __kprobes patch_text_multiple(void *addr, u32 *insn, unsigned int len)
+{
+
 	struct patch patch = {
 		.addr = addr,
 		.insn = insn,
+		.len = len
 	};
 
 	stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL);
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH v2 2/6] parisc: add spinlock to patch function
  2019-06-04 18:34 [PATCH v2 0/6] Dynamic FTRACE for PA-RISC Sven Schnelle
  2019-06-04 18:34 ` [PATCH v2 1/6] parisc: add support for patching multiple words Sven Schnelle
@ 2019-06-04 18:34 ` Sven Schnelle
  2019-06-04 18:34 ` [PATCH v2 3/6] parisc: add WARN_ON() to clear_fixmap Sven Schnelle
                   ` (3 subsequent siblings)
  5 siblings, 0 replies; 9+ messages in thread
From: Sven Schnelle @ 2019-06-04 18:34 UTC (permalink / raw)
  To: deller; +Cc: linux-parisc, Sven Schnelle

If multiple CPUs are patching code we need the spinlock
to protect against parallel fixmap maps/unmap calls.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 arch/parisc/kernel/patch.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/arch/parisc/kernel/patch.c b/arch/parisc/kernel/patch.c
index 624de41e0524..fb503f7ff60e 100644
--- a/arch/parisc/kernel/patch.c
+++ b/arch/parisc/kernel/patch.c
@@ -23,7 +23,9 @@ struct patch {
 
 static DEFINE_RAW_SPINLOCK(patch_lock);
 
-static void __kprobes *patch_map(void *addr, int fixmap, int *need_unmap)
+static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags,
+				 int *need_unmap)
+{
 	unsigned long uintaddr = (uintptr_t) addr;
 	bool module = !core_kernel_text(uintaddr);
 	struct page *page;
@@ -38,19 +40,29 @@ static void __kprobes *patch_map(void *addr, int fixmap, int *need_unmap)
 
 	*need_unmap = 1;
 	set_fixmap(fixmap, page_to_phys(page));
+	if (flags)
+		raw_spin_lock_irqsave(&patch_lock, *flags);
+	else
+		__acquire(&patch_lock);
 
 	return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
 }
 
-static void __kprobes patch_unmap(int fixmap)
+static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
 {
 	clear_fixmap(fixmap);
+
+	if (flags)
+		raw_spin_unlock_irqrestore(&patch_lock, *flags);
+	else
+		__release(&patch_lock);
 }
 
 void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
 {
 	unsigned long start = (unsigned long)addr;
 	unsigned long end = (unsigned long)addr + len;
+	unsigned long flags;
 	u32 *p, *fixmap;
 	int mapped;
 
@@ -58,7 +70,7 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
 	flush_kernel_vmap_range(addr, len);
 	flush_icache_range(start, end);
 
-	p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &mapped);
+	p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags, &mapped);
 
 	while (len >= 4) {
 		*p++ = *insn++;
@@ -72,14 +84,15 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
 			flush_kernel_vmap_range((void *)fixmap,
 						(p-fixmap) * sizeof(*p));
 			if (mapped)
-				patch_unmap(FIX_TEXT_POKE0);
-			p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &mapped);
+				patch_unmap(FIX_TEXT_POKE0, &flags);
+			p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags,
+						&mapped);
 		}
 	}
 
 	flush_kernel_vmap_range((void *)fixmap, (p-fixmap) * sizeof(*p));
 	if (mapped)
-		patch_unmap(FIX_TEXT_POKE0);
+		patch_unmap(FIX_TEXT_POKE0, &flags);
 	flush_icache_range(start, end);
 }
 
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH v2 3/6] parisc: add WARN_ON() to clear_fixmap
  2019-06-04 18:34 [PATCH v2 0/6] Dynamic FTRACE for PA-RISC Sven Schnelle
  2019-06-04 18:34 ` [PATCH v2 1/6] parisc: add support for patching multiple words Sven Schnelle
  2019-06-04 18:34 ` [PATCH v2 2/6] parisc: add spinlock to patch function Sven Schnelle
@ 2019-06-04 18:34 ` Sven Schnelle
  2019-06-04 18:34 ` [PATCH v2 4/6] parisc: use pr_debug() in kernel/module.c Sven Schnelle
                   ` (2 subsequent siblings)
  5 siblings, 0 replies; 9+ messages in thread
From: Sven Schnelle @ 2019-06-04 18:34 UTC (permalink / raw)
  To: deller; +Cc: linux-parisc, Sven Schnelle

Calling clear_fixmap() on an already cleared fixed mapping is
a bad thing to do. Add a WARN_ON() to catch such issues.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 arch/parisc/mm/fixmap.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/parisc/mm/fixmap.c b/arch/parisc/mm/fixmap.c
index c8d41b54fb19..36321bcd75ba 100644
--- a/arch/parisc/mm/fixmap.c
+++ b/arch/parisc/mm/fixmap.c
@@ -35,6 +35,9 @@ void clear_fixmap(enum fixed_addresses idx)
 	pmd_t *pmd = pmd_offset(pgd, vaddr);
 	pte_t *pte = pte_offset_kernel(pmd, vaddr);
 
+	if (WARN_ON(pte_none(*pte)))
+		return;
+
 	pte_clear(&init_mm, vaddr, pte);
 
 	flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE);
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH v2 4/6] parisc: use pr_debug() in kernel/module.c
  2019-06-04 18:34 [PATCH v2 0/6] Dynamic FTRACE for PA-RISC Sven Schnelle
                   ` (2 preceding siblings ...)
  2019-06-04 18:34 ` [PATCH v2 3/6] parisc: add WARN_ON() to clear_fixmap Sven Schnelle
@ 2019-06-04 18:34 ` Sven Schnelle
  2019-06-04 18:34 ` [PATCH v2 5/6] compiler.h: add CC_USING_PATCHABLE_FUNCTION_ENTRY Sven Schnelle
  2019-06-04 18:34 ` [PATCH v2 6/6] parisc: add dynamic ftrace Sven Schnelle
  5 siblings, 0 replies; 9+ messages in thread
From: Sven Schnelle @ 2019-06-04 18:34 UTC (permalink / raw)
  To: deller; +Cc: linux-parisc, Sven Schnelle

Instead of using our own version, switch to the generic
pr_() calls.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 arch/parisc/kernel/module.c | 44 ++++++++++++++++---------------------
 1 file changed, 19 insertions(+), 25 deletions(-)

diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index 43778420614b..3ff3b48df6e6 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -48,9 +48,9 @@
  *	However, SEGREL32 is used only for PARISC unwind entries, and we want
  *	those entries to have an absolute address, and not just an offset.
  *
- *	The unwind table mechanism has the ability to specify an offset for 
+ *	The unwind table mechanism has the ability to specify an offset for
  *	the unwind table; however, because we split off the init functions into
- *	a different piece of memory, it is not possible to do this using a 
+ *	a different piece of memory, it is not possible to do this using a
  *	single offset. Instead, we use the above hack for now.
  */
 
@@ -68,12 +68,6 @@
 #include <asm/unwind.h>
 #include <asm/sections.h>
 
-#if 0
-#define DEBUGP printk
-#else
-#define DEBUGP(fmt...)
-#endif
-
 #define RELOC_REACHABLE(val, bits) \
 	(( ( !((val) & (1<<((bits)-1))) && ((val)>>(bits)) != 0 )  ||	\
 	     ( ((val) & (1<<((bits)-1))) && ((val)>>(bits)) != (((__typeof__(val))(~0))>>((bits)+2)))) ? \
@@ -315,7 +309,7 @@ unsigned int arch_mod_section_prepend(struct module *mod,
 		* sizeof(struct stub_entry);
 }
 
-#define CONST 
+#define CONST
 int module_frob_arch_sections(CONST Elf_Ehdr *hdr,
 			      CONST Elf_Shdr *sechdrs,
 			      CONST char *secstrings,
@@ -401,7 +395,7 @@ static Elf64_Word get_got(struct module *me, unsigned long value, long addend)
 
 	got[i].addr = value;
  out:
-	DEBUGP("GOT ENTRY %d[%x] val %lx\n", i, i*sizeof(struct got_entry),
+	pr_debug("GOT ENTRY %d[%lx] val %lx\n", i, i*sizeof(struct got_entry),
 	       value);
 	return i * sizeof(struct got_entry);
 }
@@ -554,7 +548,7 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 	//unsigned long dp = (unsigned long)$global$;
 	register unsigned long dp asm ("r27");
 
-	DEBUGP("Applying relocate section %u to %u\n", relsec,
+	pr_debug("Applying relocate section %u to %u\n", relsec,
 	       targetsec);
 	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 		/* This is where to make the change */
@@ -578,7 +572,7 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 
 #if 0
 #define r(t) ELF32_R_TYPE(rel[i].r_info)==t ? #t :
-		DEBUGP("Symbol %s loc 0x%x val 0x%x addend 0x%x: %s\n",
+		pr_debug("Symbol %s loc 0x%x val 0x%x addend 0x%x: %s\n",
 			strtab + sym->st_name,
 			(uint32_t)loc, val, addend,
 			r(R_PARISC_PLABEL32)
@@ -619,7 +613,7 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 			/* See note about special handling of SEGREL32 at
 			 * the beginning of this file.
 			 */
-			*loc = fsel(val, addend); 
+			*loc = fsel(val, addend);
 			break;
 		case R_PARISC_SECREL32:
 			/* 32-bit section relative address. */
@@ -698,7 +692,7 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 	Elf_Addr loc0;
 	unsigned int targetsec = sechdrs[relsec].sh_info;
 
-	DEBUGP("Applying relocate section %u to %u\n", relsec,
+	pr_debug("Applying relocate section %u to %u\n", relsec,
 	       targetsec);
 	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 		/* This is where to make the change */
@@ -740,7 +734,7 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 		case R_PARISC_LTOFF21L:
 			/* LT-relative; left 21 bits */
 			val = get_got(me, val, addend);
-			DEBUGP("LTOFF21L Symbol %s loc %p val %lx\n",
+			pr_debug("LTOFF21L Symbol %s loc %p val %llx\n",
 			       strtab + sym->st_name,
 			       loc, val);
 			val = lrsel(val, 0);
@@ -751,14 +745,14 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 			/* LT-relative; right 14 bits */
 			val = get_got(me, val, addend);
 			val = rrsel(val, 0);
-			DEBUGP("LTOFF14R Symbol %s loc %p val %lx\n",
+			pr_debug("LTOFF14R Symbol %s loc %p val %llx\n",
 			       strtab + sym->st_name,
 			       loc, val);
 			*loc = mask(*loc, 14) | reassemble_14(val);
 			break;
 		case R_PARISC_PCREL22F:
 			/* PC-relative; 22 bits */
-			DEBUGP("PCREL22F Symbol %s loc %p val %lx\n",
+			pr_debug("PCREL22F Symbol %s loc %p val %llx\n",
 			       strtab + sym->st_name,
 			       loc, val);
 			val += addend;
@@ -790,7 +784,7 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 					val = get_stub(me, val, addend, ELF_STUB_GOT,
 						       loc0, targetsec);
 			}
-			DEBUGP("STUB FOR %s loc %lx, val %lx+%lx at %lx\n", 
+			pr_debug("STUB FOR %s loc %px, val %llx+%llx at %llx\n",
 			       strtab + sym->st_name, loc, sym->st_value,
 			       addend, val);
 			val = (val - dot - 8)/4;
@@ -810,7 +804,7 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 			/* See note about special handling of SEGREL32 at
 			 * the beginning of this file.
 			 */
-			*loc = fsel(val, addend); 
+			*loc = fsel(val, addend);
 			break;
 		case R_PARISC_SECREL32:
 			/* 32-bit section relative address. */
@@ -820,14 +814,14 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 			/* 64-bit function address */
 			if(in_local(me, (void *)(val + addend))) {
 				*loc64 = get_fdesc(me, val+addend);
-				DEBUGP("FDESC for %s at %p points to %lx\n",
+				pr_debug("FDESC for %s at %llx points to %llx\n",
 				       strtab + sym->st_name, *loc64,
 				       ((Elf_Fdesc *)*loc64)->addr);
 			} else {
 				/* if the symbol is not local to this
 				 * module then val+addend is a pointer
 				 * to the function descriptor */
-				DEBUGP("Non local FPTR64 Symbol %s loc %p val %lx\n",
+				pr_debug("Non local FPTR64 Symbol %s loc %p val %llx\n",
 				       strtab + sym->st_name,
 				       loc, val);
 				*loc64 = val + addend;
@@ -858,7 +852,7 @@ register_unwind_table(struct module *me,
 	end = table + sechdrs[me->arch.unwind_section].sh_size;
 	gp = (Elf_Addr)me->core_layout.base + me->arch.got_offset;
 
-	DEBUGP("register_unwind_table(), sect = %d at 0x%p - 0x%p (gp=0x%lx)\n",
+	pr_debug("register_unwind_table(), sect = %d at 0x%p - 0x%p (gp=0x%lx)\n",
 	       me->arch.unwind_section, table, end, gp);
 	me->arch.unwind = unwind_table_add(me->name, 0, gp, table, end);
 }
@@ -914,7 +908,7 @@ int module_finalize(const Elf_Ehdr *hdr,
 		}
 	}
 
-	DEBUGP("module %s: strtab %p, symhdr %p\n",
+	pr_debug("module %s: strtab %p, symhdr %p\n",
 	       me->name, strtab, symhdr);
 
 	if(me->arch.got_count > MAX_GOTS) {
@@ -933,7 +927,7 @@ int module_finalize(const Elf_Ehdr *hdr,
 	oldptr = (void *)symhdr->sh_addr;
 	newptr = oldptr + 1;	/* we start counting at 1 */
 	nsyms = symhdr->sh_size / sizeof(Elf_Sym);
-	DEBUGP("OLD num_symtab %lu\n", nsyms);
+	pr_debug("OLD num_symtab %lu\n", nsyms);
 
 	for (i = 1; i < nsyms; i++) {
 		oldptr++;	/* note, count starts at 1 so preincrement */
@@ -948,7 +942,7 @@ int module_finalize(const Elf_Ehdr *hdr,
 
 	}
 	nsyms = newptr - (Elf_Sym *)symhdr->sh_addr;
-	DEBUGP("NEW num_symtab %lu\n", nsyms);
+	pr_debug("NEW num_symtab %lu\n", nsyms);
 	symhdr->sh_size = nsyms * sizeof(Elf_Sym);
 
 	/* find .altinstructions section */
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH v2 5/6] compiler.h: add CC_USING_PATCHABLE_FUNCTION_ENTRY
  2019-06-04 18:34 [PATCH v2 0/6] Dynamic FTRACE for PA-RISC Sven Schnelle
                   ` (3 preceding siblings ...)
  2019-06-04 18:34 ` [PATCH v2 4/6] parisc: use pr_debug() in kernel/module.c Sven Schnelle
@ 2019-06-04 18:34 ` Sven Schnelle
  2019-06-04 18:34 ` [PATCH v2 6/6] parisc: add dynamic ftrace Sven Schnelle
  5 siblings, 0 replies; 9+ messages in thread
From: Sven Schnelle @ 2019-06-04 18:34 UTC (permalink / raw)
  To: deller; +Cc: linux-parisc, Sven Schnelle

This can be used for architectures implementing dynamic
ftrace via -fpatchable-function-entry.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 include/linux/compiler_types.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 19e58b9138a0..095d55c3834d 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -112,6 +112,8 @@ struct ftrace_likely_data {
 
 #if defined(CC_USING_HOTPATCH)
 #define notrace			__attribute__((hotpatch(0, 0)))
+#elif defined(CC_USING_PATCHABLE_FUNCTION_ENTRY)
+#define notrace			__attribute__((patchable_function_entry(0, 0)))
 #else
 #define notrace			__attribute__((__no_instrument_function__))
 #endif
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH v2 6/6] parisc: add dynamic ftrace
  2019-06-04 18:34 [PATCH v2 0/6] Dynamic FTRACE for PA-RISC Sven Schnelle
                   ` (4 preceding siblings ...)
  2019-06-04 18:34 ` [PATCH v2 5/6] compiler.h: add CC_USING_PATCHABLE_FUNCTION_ENTRY Sven Schnelle
@ 2019-06-04 18:34 ` Sven Schnelle
  5 siblings, 0 replies; 9+ messages in thread
From: Sven Schnelle @ 2019-06-04 18:34 UTC (permalink / raw)
  To: deller; +Cc: linux-parisc, Sven Schnelle

This patch implements dynamic ftrace for PA-RISC. The required mcount
call sequences can get pretty long, so instead of patching the
whole call sequence out of the functions, we are using
-fpatchable-function-entry from gcc. This puts a configurable amount of
NOPS before/at the start of the function. Taking do_sys_open() as example,
which would look like this when the call is patched out:

1036b248:       08 00 02 40     nop
1036b24c:       08 00 02 40     nop
1036b250:       08 00 02 40     nop
1036b254:       08 00 02 40     nop

1036b258 <do_sys_open>:
1036b258:       08 00 02 40     nop
1036b25c:       08 03 02 41     copy r3,r1
1036b260:       6b c2 3f d9     stw rp,-14(sp)
1036b264:       08 1e 02 43     copy sp,r3
1036b268:       6f c1 01 00     stw,ma r1,80(sp)

When ftrace gets enabled for this function the kernel will patch these
NOPs to:

1036b248:       10 19 57 20     <address of ftrace>
1036b24c:       6f c1 00 80     stw,ma r1,40(sp)
1036b250:       48 21 3f d1     ldw -18(r1),r1
1036b254:       e8 20 c0 02     bv,n r0(r1)

1036b258 <do_sys_open>:
1036b258:       e8 3f 1f df     b,l,n .-c,r1
1036b25c:       08 03 02 41     copy r3,r1
1036b260:       6b c2 3f d9     stw rp,-14(sp)
1036b264:       08 1e 02 43     copy sp,r3
1036b268:       6f c1 01 00     stw,ma r1,80(sp)

So the first NOP in do_sys_open() will be patched to jump backwards into
some minimal trampoline code which pushes a stackframe, saves r1 which
holds the return address, loads the address of the real ftrace function,
and branches to that location. For 64 Bit things are getting a bit more
complicated (and longer) because we must make sure that the address of
ftrace location is 8 byte aligned, and the offset passed to ldd for
fetching the address is 8 byte aligned as well.

Note that gcc has a bug which misplaces the function label, and needs a
patch to make dynamic ftrace work. See
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90751 for details.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 arch/parisc/Kconfig               |   2 +
 arch/parisc/Makefile              |  18 +++++
 arch/parisc/include/asm/ftrace.h  |  15 +++-
 arch/parisc/kernel/Makefile       |   9 ++-
 arch/parisc/kernel/entry.S        |  64 +++++++++++++++
 arch/parisc/kernel/ftrace.c       | 129 +++++++++++++++++++++++++++---
 arch/parisc/kernel/module.c       |  20 ++++-
 arch/parisc/kernel/module.lds     |   7 ++
 arch/parisc/kernel/vmlinux.lds.S  |   2 +
 arch/parisc/mm/fixmap.c           |   4 +-
 include/asm-generic/vmlinux.lds.h |   7 ++
 11 files changed, 259 insertions(+), 18 deletions(-)
 create mode 100644 arch/parisc/kernel/module.lds

diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 4860efa91d7b..42875ff15671 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -59,6 +59,8 @@ config PARISC
 	select HAVE_ARCH_KGDB
 	select HAVE_KPROBES
 	select HAVE_KRETPROBES
+	select HAVE_DYNAMIC_FTRACE if $(cc-option,-fpatchable-function-entry=1,1)
+	select HAVE_FTRACE_MCOUNT_RECORD if HAVE_DYNAMIC_FTRACE
 
 	help
 	  The PA-RISC microprocessor is designed by Hewlett-Packard and used
diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile
index c19af26febe6..58d46665cad9 100644
--- a/arch/parisc/Makefile
+++ b/arch/parisc/Makefile
@@ -47,6 +47,24 @@ ifneq ($(SUBARCH),$(UTS_MACHINE))
 	endif
 endif
 
+ifdef CONFIG_DYNAMIC_FTRACE
+ifdef CONFIG_64BIT
+NOP_COUNT := 8
+else
+NOP_COUNT := 5
+endif
+
+export CC_USING_RECORD_MCOUNT:=1
+export CC_USING_PATCHABLE_FUNCTION_ENTRY:=1
+
+KBUILD_AFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY=1
+KBUILD_CFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY=1 \
+		 -DFTRACE_PATCHABLE_FUNCTION_SIZE=$(NOP_COUNT)
+
+CC_FLAGS_FTRACE := -fpatchable-function-entry=$(NOP_COUNT),$(shell echo $$(($(NOP_COUNT)-1)))
+KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/parisc/kernel/module.lds
+endif
+
 OBJCOPY_FLAGS =-O binary -R .note -R .comment -S
 
 cflags-y	:= -pipe
diff --git a/arch/parisc/include/asm/ftrace.h b/arch/parisc/include/asm/ftrace.h
index 42b2c75a1645..958c0aa5dbb2 100644
--- a/arch/parisc/include/asm/ftrace.h
+++ b/arch/parisc/include/asm/ftrace.h
@@ -5,12 +5,23 @@
 #ifndef __ASSEMBLY__
 extern void mcount(void);
 
-#define MCOUNT_INSN_SIZE 4
-
+#define MCOUNT_ADDR		((unsigned long)mcount)
+#define MCOUNT_INSN_SIZE	4
+#define CC_USING_NOP_MCOUNT
 extern unsigned long sys_call_table[];
 
 extern unsigned long return_address(unsigned int);
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern void ftrace_caller(void);
+
+struct dyn_arch_ftrace {
+};
+
+unsigned long ftrace_call_adjust(unsigned long addr);
+
+#endif
+
 #define ftrace_return_address(n) return_address(n)
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile
index fc0df5c44468..c232266b517c 100644
--- a/arch/parisc/kernel/Makefile
+++ b/arch/parisc/kernel/Makefile
@@ -14,10 +14,11 @@ obj-y	     	:= cache.o pacache.o setup.o pdt.o traps.o time.o irq.o \
 
 ifdef CONFIG_FUNCTION_TRACER
 # Do not profile debug and lowlevel utilities
-CFLAGS_REMOVE_ftrace.o = -pg
-CFLAGS_REMOVE_cache.o = -pg
-CFLAGS_REMOVE_perf.o = -pg
-CFLAGS_REMOVE_unwind.o = -pg
+CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_cache.o =  $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_perf.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_unwind.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_patch.o = $(CC_FLAGS_FTRACE)
 endif
 
 obj-$(CONFIG_SMP)	+= smp.o
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index a1fc04570ade..c246cefa0737 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -2025,6 +2025,70 @@ ftrace_stub:
 #endif
 ENDPROC_CFI(mcount)
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+#ifdef CONFIG_64BIT
+#define FTRACE_FRAME_SIZE (2*FRAME_SIZE)
+#else
+#define FTRACE_FRAME_SIZE FRAME_SIZE
+#endif
+ENTRY_CFI(ftrace_caller, caller,frame=FTRACE_FRAME_SIZE,CALLS,SAVE_RP,SAVE_SP)
+ftrace_caller:
+	.global ftrace_caller
+
+	STREG	%r3, -FTRACE_FRAME_SIZE+1*REG_SZ(%sp)
+	ldo	-FTRACE_FRAME_SIZE(%sp), %r3
+	STREG	%rp, -RP_OFFSET(%r3)
+
+	/* Offset 0 is already allocated for %r1 */
+	STREG	%r23, 2*REG_SZ(%r3)
+	STREG	%r24, 3*REG_SZ(%r3)
+	STREG	%r25, 4*REG_SZ(%r3)
+	STREG	%r26, 5*REG_SZ(%r3)
+	STREG	%r28, 6*REG_SZ(%r3)
+	STREG	%r29, 7*REG_SZ(%r3)
+#ifdef CONFIG_64BIT
+	STREG	%r19, 8*REG_SZ(%r3)
+	STREG	%r20, 9*REG_SZ(%r3)
+	STREG	%r21, 10*REG_SZ(%r3)
+	STREG	%r22, 11*REG_SZ(%r3)
+	STREG	%r27, 12*REG_SZ(%r3)
+	STREG	%r31, 13*REG_SZ(%r3)
+	loadgp
+	ldo	-16(%sp),%r29
+#endif
+	LDREG	0(%r3), %r25
+	copy	%rp, %r26
+	ldo	-8(%r25), %r25
+	b,l	ftrace_function_trampoline, %rp
+	copy	%r3, %r24
+
+	LDREG	-RP_OFFSET(%r3), %rp
+	LDREG	2*REG_SZ(%r3), %r23
+	LDREG	3*REG_SZ(%r3), %r24
+	LDREG	4*REG_SZ(%r3), %r25
+	LDREG	5*REG_SZ(%r3), %r26
+	LDREG	6*REG_SZ(%r3), %r28
+	LDREG	7*REG_SZ(%r3), %r29
+#ifdef CONFIG_64BIT
+	LDREG	8*REG_SZ(%r3), %r19
+	LDREG	9*REG_SZ(%r3), %r20
+	LDREG	10*REG_SZ(%r3), %r21
+	LDREG	11*REG_SZ(%r3), %r22
+	LDREG	12*REG_SZ(%r3), %r27
+	LDREG	13*REG_SZ(%r3), %r31
+#endif
+	LDREG	1*REG_SZ(%r3), %r3
+
+	LDREGM	-FTRACE_FRAME_SIZE(%sp), %r1
+	/* Adjust return point to jump back to beginning of traced function */
+	ldo	-4(%r1), %r1
+	bv,n	(%r1)
+
+ENDPROC_CFI(ftrace_caller)
+
+#endif
+
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	.align 8
 ENTRY_CFI(return_to_handler, caller,frame=FRAME_SIZE)
diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c
index a28f915993b1..d784ccdd8fef 100644
--- a/arch/parisc/kernel/ftrace.c
+++ b/arch/parisc/kernel/ftrace.c
@@ -7,17 +7,17 @@
  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
  *
  * future possible enhancements:
- * 	- add CONFIG_DYNAMIC_FTRACE
  *	- add CONFIG_STACK_TRACER
  */
 
 #include <linux/init.h>
 #include <linux/ftrace.h>
+#include <linux/uaccess.h>
 
 #include <asm/assembly.h>
 #include <asm/sections.h>
 #include <asm/ftrace.h>
-
+#include <asm/patch.h>
 
 #define __hot __attribute__ ((__section__ (".text.hot")))
 
@@ -50,13 +50,11 @@ void notrace __hot ftrace_function_trampoline(unsigned long parent,
 				unsigned long self_addr,
 				unsigned long org_sp_gr3)
 {
-	extern ftrace_func_t ftrace_trace_function;  /* depends on CONFIG_DYNAMIC_FTRACE */
-
-	if (ftrace_trace_function != ftrace_stub) {
-		/* struct ftrace_ops *op, struct pt_regs *regs); */
-		ftrace_trace_function(parent, self_addr, NULL, NULL);
-		return;
-	}
+#ifndef CONFIG_DYNAMIC_FTRACE
+	extern ftrace_func_t ftrace_trace_function;
+#endif
+	if (ftrace_trace_function != ftrace_stub)
+		ftrace_trace_function(self_addr, parent, NULL, NULL);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub ||
@@ -75,3 +73,116 @@ void notrace __hot ftrace_function_trampoline(unsigned long parent,
 #endif
 }
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+int ftrace_enable_ftrace_graph_caller(void)
+{
+	return 0;
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+int __init ftrace_dyn_arch_init(void)
+{
+	return 0;
+}
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+	return 0;
+}
+
+unsigned long ftrace_call_adjust(unsigned long addr)
+{
+	return addr+(FTRACE_PATCHABLE_FUNCTION_SIZE-1)*4;
+}
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+	u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
+	u32 *tramp;
+	int size, ret, i;
+	void *ip;
+
+#ifdef CONFIG_64BIT
+	unsigned long addr2 =
+		(unsigned long)dereference_function_descriptor((void *)addr);
+
+	u32 ftrace_trampoline[] = {
+		0x73c10208, /* std,ma r1,100(sp) */
+		0x0c2110c1, /* ldd -10(r1),r1 */
+		0xe820d002, /* bve,n (r1) */
+		addr2 >> 32,
+		addr2 & 0xffffffff,
+		0xe83f1fd7, /* b,l,n .-14,r1 */
+	};
+
+	u32 ftrace_trampoline_unaligned[] = {
+		addr2 >> 32,
+		addr2 & 0xffffffff,
+		0x37de0200, /* ldo 100(sp),sp */
+		0x73c13e01, /* std r1,-100(sp) */
+		0x34213ff9, /* ldo -4(r1),r1 */
+		0x50213fc1, /* ldd -20(r1),r1 */
+		0xe820d002, /* bve,n (r1) */
+		0xe83f1fcf, /* b,l,n .-20,r1 */
+	};
+
+	BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline_unaligned) >
+				FTRACE_PATCHABLE_FUNCTION_SIZE);
+#else
+	u32 ftrace_trampoline[] = {
+		(u32)addr,
+		0x6fc10080, /* stw,ma r1,40(sp) */
+		0x48213fd1, /* ldw -18(r1),r1 */
+		0xe820c002, /* bv,n r0(r1) */
+		0xe83f1fdf, /* b,l,n .-c,r1 */
+	};
+#endif
+
+	BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline) >
+				FTRACE_PATCHABLE_FUNCTION_SIZE);
+
+	size = sizeof(ftrace_trampoline);
+	tramp = ftrace_trampoline;
+
+#ifdef CONFIG_64BIT
+	if (rec->ip & 0x4) {
+		size = sizeof(ftrace_trampoline_unaligned);
+		tramp = ftrace_trampoline_unaligned;
+	}
+#endif
+
+	ip = (void *)(rec->ip + 4 - size);
+
+	ret = probe_kernel_read(insn, ip, size);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < size / 4; i++) {
+		if (insn[i] != INSN_NOP)
+			return -EINVAL;
+	}
+
+	__patch_text_multiple(ip, tramp, size);
+	return 0;
+}
+
+int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
+		    unsigned long addr)
+{
+	u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(insn); i++)
+		insn[i] = INSN_NOP;
+
+	__patch_text_multiple((void *)rec->ip + 4 - sizeof(insn),
+			      insn, sizeof(insn));
+	return 0;
+}
+#endif
diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c
index 3ff3b48df6e6..ed6640527534 100644
--- a/arch/parisc/kernel/module.c
+++ b/arch/parisc/kernel/module.c
@@ -873,6 +873,7 @@ int module_finalize(const Elf_Ehdr *hdr,
 	const char *strtab = NULL;
 	const Elf_Shdr *s;
 	char *secstrings;
+	int err, symindex = -1;
 	Elf_Sym *newptr, *oldptr;
 	Elf_Shdr *symhdr = NULL;
 #ifdef DEBUG
@@ -899,6 +900,7 @@ int module_finalize(const Elf_Ehdr *hdr,
 		if(sechdrs[i].sh_type == SHT_SYMTAB
 		   && (sechdrs[i].sh_flags & SHF_ALLOC)) {
 			int strindex = sechdrs[i].sh_link;
+			symindex = i;
 			/* FIXME: AWFUL HACK
 			 * The cast is to drop the const from
 			 * the sechdrs pointer */
@@ -954,8 +956,24 @@ int module_finalize(const Elf_Ehdr *hdr,
 		if (!strcmp(".altinstructions", secname))
 			/* patch .altinstructions */
 			apply_alternatives(aseg, aseg + s->sh_size, me->name);
-	}
 
+		/* For 32 bit kernels we're compiling modules with
+		 * -ffunction-sections so we must relocate the addresses in the
+		 *__mcount_loc section.
+		 */
+		if (symindex != -1 && !strcmp(secname, "__mcount_loc")) {
+			if (s->sh_type == SHT_REL)
+				err = apply_relocate((Elf_Shdr *)sechdrs,
+							strtab, symindex,
+							s - sechdrs, me);
+			else if (s->sh_type == SHT_RELA)
+				err = apply_relocate_add((Elf_Shdr *)sechdrs,
+							strtab, symindex,
+							s - sechdrs, me);
+			if (err)
+				return err;
+		}
+	}
 	return 0;
 }
 
diff --git a/arch/parisc/kernel/module.lds b/arch/parisc/kernel/module.lds
new file mode 100644
index 000000000000..1a9a92aca5c8
--- /dev/null
+++ b/arch/parisc/kernel/module.lds
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+SECTIONS {
+	__mcount_loc : {
+		*(__patchable_function_entries)
+	}
+}
diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S
index cd33b4feacb1..99cd24f2ea01 100644
--- a/arch/parisc/kernel/vmlinux.lds.S
+++ b/arch/parisc/kernel/vmlinux.lds.S
@@ -18,6 +18,8 @@
 				*(.data..vm0.pgd) \
 				*(.data..vm0.pte)
 
+#define CC_USING_PATCHABLE_FUNCTION_ENTRY
+
 #include <asm-generic/vmlinux.lds.h>
 
 /* needed for the processor specific cache alignment size */	
diff --git a/arch/parisc/mm/fixmap.c b/arch/parisc/mm/fixmap.c
index 36321bcd75ba..474cd241c150 100644
--- a/arch/parisc/mm/fixmap.c
+++ b/arch/parisc/mm/fixmap.c
@@ -10,7 +10,7 @@
 #include <asm/cacheflush.h>
 #include <asm/fixmap.h>
 
-void set_fixmap(enum fixed_addresses idx, phys_addr_t phys)
+void notrace set_fixmap(enum fixed_addresses idx, phys_addr_t phys)
 {
 	unsigned long vaddr = __fix_to_virt(idx);
 	pgd_t *pgd = pgd_offset_k(vaddr);
@@ -28,7 +28,7 @@ void set_fixmap(enum fixed_addresses idx, phys_addr_t phys)
 	flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE);
 }
 
-void clear_fixmap(enum fixed_addresses idx)
+void notrace clear_fixmap(enum fixed_addresses idx)
 {
 	unsigned long vaddr = __fix_to_virt(idx);
 	pgd_t *pgd = pgd_offset_k(vaddr);
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 088987e9a3ea..ca42182992a5 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -110,10 +110,17 @@
 #endif
 
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
+#ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
+#define MCOUNT_REC()	. = ALIGN(8);				\
+			__start_mcount_loc = .;			\
+			KEEP(*(__patchable_function_entries))	\
+			__stop_mcount_loc = .;
+#else
 #define MCOUNT_REC()	. = ALIGN(8);				\
 			__start_mcount_loc = .;			\
 			KEEP(*(__mcount_loc))			\
 			__stop_mcount_loc = .;
+#endif
 #else
 #define MCOUNT_REC()
 #endif
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/6] parisc: add support for patching multiple words
  2019-06-04 18:34 ` [PATCH v2 1/6] parisc: add support for patching multiple words Sven Schnelle
@ 2019-06-04 19:21   ` Rolf Eike Beer
  2019-06-05 20:21     ` Sven Schnelle
  0 siblings, 1 reply; 9+ messages in thread
From: Rolf Eike Beer @ 2019-06-04 19:21 UTC (permalink / raw)
  To: Sven Schnelle; +Cc: deller, linux-parisc

[-- Attachment #1: Type: text/plain, Size: 256 bytes --]

Sven Schnelle wrote:
> +	while (len >= 4) {
> +		*p++ = *insn++;
> +		addr += sizeof(u32);
> +		len -= sizeof(u32);
> +		if (len && !((unsigned long)addr & ~PAGE_MASK)) {

if (len && offset_in_page(addr) == 0)

This is a bit more obvious to me. YMMV.

Eike

[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 195 bytes --]

^ permalink raw reply	[flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/6] parisc: add support for patching multiple words
  2019-06-04 19:21   ` Rolf Eike Beer
@ 2019-06-05 20:21     ` Sven Schnelle
  0 siblings, 0 replies; 9+ messages in thread
From: Sven Schnelle @ 2019-06-05 20:21 UTC (permalink / raw)
  To: Rolf Eike Beer; +Cc: deller, linux-parisc

Hi,

On Tue, Jun 04, 2019 at 09:21:34PM +0200, Rolf Eike Beer wrote:
> Sven Schnelle wrote:
> > +	while (len >= 4) {
> > +		*p++ = *insn++;
> > +		addr += sizeof(u32);
> > +		len -= sizeof(u32);
> > +		if (len && !((unsigned long)addr & ~PAGE_MASK)) {
> 
> if (len && offset_in_page(addr) == 0)
> 
> This is a bit more obvious to me. YMMV.

It is. I'll update the patch and send a v3. Thanks!

Sven

^ permalink raw reply	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2019-06-05 20:21 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-06-04 18:34 [PATCH v2 0/6] Dynamic FTRACE for PA-RISC Sven Schnelle
2019-06-04 18:34 ` [PATCH v2 1/6] parisc: add support for patching multiple words Sven Schnelle
2019-06-04 19:21   ` Rolf Eike Beer
2019-06-05 20:21     ` Sven Schnelle
2019-06-04 18:34 ` [PATCH v2 2/6] parisc: add spinlock to patch function Sven Schnelle
2019-06-04 18:34 ` [PATCH v2 3/6] parisc: add WARN_ON() to clear_fixmap Sven Schnelle
2019-06-04 18:34 ` [PATCH v2 4/6] parisc: use pr_debug() in kernel/module.c Sven Schnelle
2019-06-04 18:34 ` [PATCH v2 5/6] compiler.h: add CC_USING_PATCHABLE_FUNCTION_ENTRY Sven Schnelle
2019-06-04 18:34 ` [PATCH v2 6/6] parisc: add dynamic ftrace Sven Schnelle

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).