sections: Unify kernel sections range check and use

Started by Kefeng Wang on Sep 26, 2021 · 12 messages from 2 authors · Last reply Sep 29, 2021

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9 patches, 11 files

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STALE1866d SUPERSEDED

Status: Superseded by v4 (posted 2021-09-30). [go to v4]

Revision v3 (4 revisions archived).

Revisions (4)
  1. v1
  2. v2 [diff against previous]
  3. v3 current [diff against previous]
  4. v4 [diff against previous]

open the first message on its own page

  1. [PATCH v3 1/9] kallsyms: Remove arch specific text and data check
    Revisions and related patches
    Revisions (4)
    1. v1
    2. v2 [diff against previous]
    3. v3 current [diff against previous]
    4. v4 [diff against previous]
  2. [PATCH v3 2/9] kallsyms: Fix address-checks for kernel related range
    Revisions and related patches
    Revisions (4)
    1. v1
    2. v2 [diff against previous]
    3. v3 current [diff against previous]
    4. v4 [diff against previous]
  3. [PATCH v3 3/9] sections: Move and rename core_kernel_data() to is_kernel_core_data()
    Revisions and related patches
    Revisions (4)
    1. v1
    2. v2 [diff against previous]
    3. v3 current [diff against previous]
    4. v4 [diff against previous]
  4. [PATCH v3 4/9] sections: Move is_kernel_inittext() into sections.h
    Revisions and related patches
    Revisions (4)
    1. v1
    2. v2 [diff against previous]
    3. v3 current [diff against previous]
    4. v4 [diff against previous]
  5. [PATCH v3 5/9] x86: mm: Rename __is_kernel_text() to is_x86_32_kernel_text()
    Revisions and related patches
    Revisions (4)
    1. v1
    2. v2 [diff against previous]
    3. v3 current [diff against previous]
    4. v4 [diff against previous]
  6. [PATCH v3 7/9] mm: kasan: Use is_kernel() helper
    Revisions and related patches
    Revisions (4)
    1. v1
    2. v2 [diff against previous]
    3. v3 current [diff against previous]
    4. v4 [diff against previous]
  7. [PATCH v3 8/9] extable: Use is_kernel_text() helper
    Revisions and related patches
    Revisions (3)
    1. v1
    2. v3 current [diff against previous]
    3. v4 [diff against previous]
  8. [PATCH v3 9/9] powerpc/mm: Use is_kernel_text() and is_kernel_inittext() helper
    Revisions and related patches
    Revisions (3)
    1. v1
    2. v3 current [diff against previous]
    3. v4 [diff against previous]
  9. [PATCH v3 6/9] sections: Provide internal __is_kernel() and __is_kernel_text() helper
    Revisions and related patches
    Revisions (4)
    1. v1
    2. v2 [diff against previous]
    3. v3 current [diff against previous]
    4. v4 [diff against previous]
Message details and related content
There are three head files(kallsyms.h, kernel.h and sections.h) which
include the kernel sections range check, let's make some cleanup and
unify them.

1. cleanup arch specific text/data check and fix address boundary check
   in kallsyms.h
2. make all the basic/core kernel range check function into sections.h
3. update all the callers, and use the helper in sections.h to simplify
   the code

After this series, we have 5 APIs about kernel sections range check in
sections.h

 * is_kernel_rodata()		--- already in sections.h
 * is_kernel_core_data()	--- come from core_kernel_data() in kernel.h
 * is_kernel_inittext()		--- come from kernel.h and kallsyms.h
 * __is_kernel_text()		--- add new internal helper
 * __is_kernel()		--- add new internal helper

Note: For the last two helpers, people should not use directly, consider to
      use corresponding function in kallsyms.h.

v3:
- Add Steven's RB to patch2
- Introduce two internal helper, then use is_kernel_text() in core_kernel_text()
  and is_kernel() in kernel_or_module_addr() suggested by Steven

v2:
https://lore.kernel.org/linux-arch/20210728081320.20394-1-wangkefeng.wang@huawei.com/
- add ACK/RW to patch2, and drop inappropriate fix tag
- keep 'core' to check kernel data, suggestted by Steven Rostedt
  [off-list ref], rename is_kernel_data() to is_kernel_core_data()
- drop patch8 which is merged
- drop patch9 which is resend independently

v1:
https://lore.kernel.org/linux-arch/20210626073439.150586-1-wangkefeng.wang@huawei.com

Cc: <redacted>
Cc: <redacted> 

29 more lines

[PATCH v3 1/9] kallsyms: Remove arch specific text and data check

Message details and related content
After commit 4ba66a976072 ("arch: remove blackfin port"),
no need arch-specific text/data check.

Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kefeng Wang <redacted>
---
 include/asm-generic/sections.h | 16 ----------------
 include/linux/kallsyms.h       |  3 +--
 kernel/locking/lockdep.c       |  3 ---
 3 files changed, 1 insertion(+), 21 deletions(-)
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index d16302d3eb59..817309e289db 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -64,22 +64,6 @@ extern __visible const void __nosave_begin, __nosave_end;
 #define dereference_kernel_function_descriptor(p) ((void *)(p))
 #endif
 
-/* random extra sections (if any).  Override
- * in asm/sections.h */
-#ifndef arch_is_kernel_text
-static inline int arch_is_kernel_text(unsigned long addr)
-{
-	return 0;
-}
-#endif
-
-#ifndef arch_is_kernel_data
-static inline int arch_is_kernel_data(unsigned long addr)
-{
-	return 0;
-}
-#endif
-
 /*
  * Check if an address is part of freed initmem. This is needed on architectures
  * with virt == phys kernel mapping, for code that wants to check if an address
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 6851c2313cad..2a241e3f063f 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -34,8 +34,7 @@ static inline int is_kernel_inittext(unsigned long addr)
 
 static inline int is_kernel_text(unsigned long addr)
 {
-	if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext) ||
-	    arch_is_kernel_text(addr))
+	if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext))
 		return 1;
 	return in_gate_area_no_mm(addr);
 }
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 7096384dc60f..dcdbcee391cd 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -803,9 +803,6 @@ static int static_obj(const void *obj)
 	if ((addr >= start) && (addr < end))
 		return 1;
 
-	if (arch_is_kernel_data(addr))
-		return 1;
-
 	/*
 	 * in-kernel percpu var?
 	 */
-- 
2.26.2

[PATCH v3 2/9] kallsyms: Fix address-checks for kernel related range

Message details and related content
The is_kernel_inittext/is_kernel_text/is_kernel function should not
include the end address(the labels _einittext, _etext and _end) when
check the address range, the issue exists since Linux v2.6.12.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Sergey Senozhatsky <redacted>
Cc: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Kefeng Wang <redacted>
---
 include/linux/kallsyms.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 2a241e3f063f..b016c62f30a6 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -27,21 +27,21 @@ struct module;
 static inline int is_kernel_inittext(unsigned long addr)
 {
 	if (addr >= (unsigned long)_sinittext
-	    && addr <= (unsigned long)_einittext)
+	    && addr < (unsigned long)_einittext)
 		return 1;
 	return 0;
 }
 
 static inline int is_kernel_text(unsigned long addr)
 {
-	if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext))
+	if ((addr >= (unsigned long)_stext && addr < (unsigned long)_etext))
 		return 1;
 	return in_gate_area_no_mm(addr);
 }
 
 static inline int is_kernel(unsigned long addr)
 {
-	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
+	if (addr >= (unsigned long)_stext && addr < (unsigned long)_end)
 		return 1;
 	return in_gate_area_no_mm(addr);
 }
-- 
2.26.2

[PATCH v3 3/9] sections: Move and rename core_kernel_data() to is_kernel_core_data()

Message details and related content
Move core_kernel_data() into sections.h and rename it to
is_kernel_core_data(), also make it return bool value, then
update all the callers.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Kefeng Wang <redacted>
---
 include/asm-generic/sections.h | 16 ++++++++++++++++
 include/linux/kernel.h         |  1 -
 kernel/extable.c               | 18 ------------------
 kernel/trace/ftrace.c          |  2 +-
 net/sysctl_net.c               |  2 +-
 5 files changed, 18 insertions(+), 21 deletions(-)
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index 817309e289db..24780c0f40b1 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -142,6 +142,22 @@ static inline bool init_section_intersects(void *virt, size_t size)
 	return memory_intersects(__init_begin, __init_end, virt, size);
 }
 
+/**
+ * is_kernel_core_data - checks if the pointer address is located in the
+ *			 .data section
+ *
+ * @addr: address to check
+ *
+ * Returns: true if the address is located in .data, false otherwise.
+ * Note: On some archs it may return true for core RODATA, and false
+ *       for others. But will always be true for core RW data.
+ */
+static inline bool is_kernel_core_data(unsigned long addr)
+{
+	return addr >= (unsigned long)_sdata &&
+	       addr < (unsigned long)_edata;
+}
+
 /**
  * is_kernel_rodata - checks if the pointer address is located in the
  *                    .rodata section
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 2776423a587e..e5a9af8a4e20 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -230,7 +230,6 @@ extern char *next_arg(char *args, char **param, char **val);
 
 extern int core_kernel_text(unsigned long addr);
 extern int init_kernel_text(unsigned long addr);
-extern int core_kernel_data(unsigned long addr);
 extern int __kernel_text_address(unsigned long addr);
 extern int kernel_text_address(unsigned long addr);
 extern int func_ptr_is_kernel_text(void *ptr);
diff --git a/kernel/extable.c b/kernel/extable.c
index b0ea5eb0c3b4..da26203841d4 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -82,24 +82,6 @@ int notrace core_kernel_text(unsigned long addr)
 	return 0;
 }
 
-/**
- * core_kernel_data - tell if addr points to kernel data
- * @addr: address to test
- *
- * Returns true if @addr passed in is from the core kernel data
- * section.
- *
- * Note: On some archs it may return true for core RODATA, and false
- *  for others. But will always be true for core RW data.
- */
-int core_kernel_data(unsigned long addr)
-{
-	if (addr >= (unsigned long)_sdata &&
-	    addr < (unsigned long)_edata)
-		return 1;
-	return 0;
-}
-
 int __kernel_text_address(unsigned long addr)
 {
 	if (kernel_text_address(addr))
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 7efbc8aaf7f6..f15badf31f52 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -323,7 +323,7 @@ int __register_ftrace_function(struct ftrace_ops *ops)
 	if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
 		return -EBUSY;
 
-	if (!core_kernel_data((unsigned long)ops))
+	if (!is_kernel_core_data((unsigned long)ops))
 		ops->flags |= FTRACE_OPS_FL_DYNAMIC;
 
 	add_ftrace_ops(&ftrace_ops_list, ops);
diff --git a/net/sysctl_net.c b/net/sysctl_net.c
index f6cb0d4d114c..4b45ed631eb8 100644
--- a/net/sysctl_net.c
+++ b/net/sysctl_net.c
@@ -144,7 +144,7 @@ static void ensure_safe_net_sysctl(struct net *net, const char *path,
 		addr = (unsigned long)ent->data;
 		if (is_module_address(addr))
 			where = "module";
-		else if (core_kernel_data(addr))
+		else if (is_kernel_core_data(addr))
 			where = "kernel";
 		else
 			continue;
-- 
2.26.2

[PATCH v3 4/9] sections: Move is_kernel_inittext() into sections.h

Message details and related content
The is_kernel_inittext() and init_kernel_text() are with same
functionality, let's just keep is_kernel_inittext() and move
it into sections.h, then update all the callers.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <redacted>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: x86@kernel.org
Signed-off-by: Kefeng Wang <redacted>
---
 arch/x86/kernel/unwind_orc.c   |  2 +-
 include/asm-generic/sections.h | 14 ++++++++++++++
 include/linux/kallsyms.h       |  8 --------
 include/linux/kernel.h         |  1 -
 kernel/extable.c               | 12 ++----------
 5 files changed, 17 insertions(+), 20 deletions(-)
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index a1202536fc57..d92ec2ced059 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -175,7 +175,7 @@ static struct orc_entry *orc_find(unsigned long ip)
 	}
 
 	/* vmlinux .init slow lookup: */
-	if (init_kernel_text(ip))
+	if (is_kernel_inittext(ip))
 		return __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
 				  __stop_orc_unwind_ip - __start_orc_unwind_ip, ip);
 
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index 24780c0f40b1..811583ca8bd0 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -172,4 +172,18 @@ static inline bool is_kernel_rodata(unsigned long addr)
 	       addr < (unsigned long)__end_rodata;
 }
 
+/**
+ * is_kernel_inittext - checks if the pointer address is located in the
+ *                      .init.text section
+ *
+ * @addr: address to check
+ *
+ * Returns: true if the address is located in .init.text, false otherwise.
+ */
+static inline bool is_kernel_inittext(unsigned long addr)
+{
+	return addr >= (unsigned long)_sinittext &&
+	       addr < (unsigned long)_einittext;
+}
+
 #endif /* _ASM_GENERIC_SECTIONS_H_ */
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index b016c62f30a6..8a9d329c927c 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -24,14 +24,6 @@
 struct cred;
 struct module;
 
-static inline int is_kernel_inittext(unsigned long addr)
-{
-	if (addr >= (unsigned long)_sinittext
-	    && addr < (unsigned long)_einittext)
-		return 1;
-	return 0;
-}
-
 static inline int is_kernel_text(unsigned long addr)
 {
 	if ((addr >= (unsigned long)_stext && addr < (unsigned long)_etext))
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index e5a9af8a4e20..445d0dceefb8 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -229,7 +229,6 @@ extern bool parse_option_str(const char *str, const char *option);
 extern char *next_arg(char *args, char **param, char **val);
 
 extern int core_kernel_text(unsigned long addr);
-extern int init_kernel_text(unsigned long addr);
 extern int __kernel_text_address(unsigned long addr);
 extern int kernel_text_address(unsigned long addr);
 extern int func_ptr_is_kernel_text(void *ptr);
diff --git a/kernel/extable.c b/kernel/extable.c
index da26203841d4..98ca627ac5ef 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -62,14 +62,6 @@ const struct exception_table_entry *search_exception_tables(unsigned long addr)
 	return e;
 }
 
-int init_kernel_text(unsigned long addr)
-{
-	if (addr >= (unsigned long)_sinittext &&
-	    addr < (unsigned long)_einittext)
-		return 1;
-	return 0;
-}
-
 int notrace core_kernel_text(unsigned long addr)
 {
 	if (addr >= (unsigned long)_stext &&
@@ -77,7 +69,7 @@ int notrace core_kernel_text(unsigned long addr)
 		return 1;
 
 	if (system_state < SYSTEM_RUNNING &&
-	    init_kernel_text(addr))
+	    is_kernel_inittext(addr))
 		return 1;
 	return 0;
 }
@@ -94,7 +86,7 @@ int __kernel_text_address(unsigned long addr)
 	 * Since we are after the module-symbols check, there's
 	 * no danger of address overlap:
 	 */
-	if (init_kernel_text(addr))
+	if (is_kernel_inittext(addr))
 		return 1;
 	return 0;
 }
-- 
2.26.2

[PATCH v3 5/9] x86: mm: Rename __is_kernel_text() to is_x86_32_kernel_text()

Message details and related content
Commit b56cd05c55a1 ("x86/mm: Rename is_kernel_text to __is_kernel_text"),
add '__' prefix not to get in conflict with existing is_kernel_text() in
<linux/kallsyms.h>.

We will add __is_kernel_text() for the basic kernel text range check in the
next patch, so use private is_x86_32_kernel_text() naming for x86 special
check.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Signed-off-by: Kefeng Wang <redacted>
---
 arch/x86/mm/init_32.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index bd90b8fe81e4..523743ee9dea 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -238,11 +238,7 @@ page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 	}
 }
 
-/*
- * The <linux/kallsyms.h> already defines is_kernel_text,
- * using '__' prefix not to get in conflict.
- */
-static inline int __is_kernel_text(unsigned long addr)
+static inline int is_x86_32_kernel_text(unsigned long addr)
 {
 	if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end)
 		return 1;
@@ -333,8 +329,8 @@ kernel_physical_mapping_init(unsigned long start,
 				addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
 					PAGE_OFFSET + PAGE_SIZE-1;
 
-				if (__is_kernel_text(addr) ||
-				    __is_kernel_text(addr2))
+				if (is_x86_32_kernel_text(addr) ||
+				    is_x86_32_kernel_text(addr2))
 					prot = PAGE_KERNEL_LARGE_EXEC;
 
 				pages_2m++;
@@ -359,7 +355,7 @@ kernel_physical_mapping_init(unsigned long start,
 				 */
 				pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
 
-				if (__is_kernel_text(addr))
+				if (is_x86_32_kernel_text(addr))
 					prot = PAGE_KERNEL_EXEC;
 
 				pages_4k++;
@@ -820,7 +816,7 @@ static void mark_nxdata_nx(void)
 	 */
 	unsigned long start = PFN_ALIGN(_etext);
 	/*
-	 * This comes from __is_kernel_text upper limit. Also HPAGE where used:
+	 * This comes from is_x86_32_kernel_text upper limit. Also HPAGE where used:
 	 */
 	unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start;
 
-- 
2.26.2

[PATCH v3 7/9] mm: kasan: Use is_kernel() helper

Message details and related content
Directly use is_kernel() helper in kernel_or_module_addr().

Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Kefeng Wang <redacted>
---
 mm/kasan/report.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 3239fd8f8747..1c955e1c98d5 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -226,7 +226,7 @@ static void describe_object(struct kmem_cache *cache, void *object,
 
 static inline bool kernel_or_module_addr(const void *addr)
 {
-	if (addr >= (void *)_stext && addr < (void *)_end)
+	if (is_kernel((unsigned long)addr))
 		return true;
 	if (is_module_address((unsigned long)addr))
 		return true;
-- 
2.26.2

[PATCH v3 8/9] extable: Use is_kernel_text() helper

Message details and related content
The core_kernel_text() should check the gate area, as it is part
of kernel text range.

Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Kefeng Wang <redacted>
---
 kernel/extable.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/extable.c b/kernel/extable.c
index 98ca627ac5ef..0ba383d850ff 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -64,8 +64,7 @@ const struct exception_table_entry *search_exception_tables(unsigned long addr)
 
 int notrace core_kernel_text(unsigned long addr)
 {
-	if (addr >= (unsigned long)_stext &&
-	    addr < (unsigned long)_etext)
+	if (is_kernel_text(addr))
 		return 1;
 
 	if (system_state < SYSTEM_RUNNING &&
-- 
2.26.2

[PATCH v3 9/9] powerpc/mm: Use is_kernel_text() and is_kernel_inittext() helper

Message details and related content
Use is_kernel_text() and is_kernel_inittext() helper to simplify code,
also drop etext, _stext, _sinittext, _einittext declaration which
already declared in section.h.

Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <redacted>
Cc: <redacted>
Signed-off-by: Kefeng Wang <redacted>
---
 arch/powerpc/mm/pgtable_32.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index dcf5ecca19d9..13c798308c2e 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -33,8 +33,6 @@
 
 #include <mm/mmu_decl.h>
 
-extern char etext[], _stext[], _sinittext[], _einittext[];
-
 static u8 early_fixmap_pagetable[FIXMAP_PTE_SIZE] __page_aligned_data;
 
 notrace void __init early_ioremap_init(void)
@@ -104,14 +102,13 @@ static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
 {
 	unsigned long v, s;
 	phys_addr_t p;
-	int ktext;
+	bool ktext;
 
 	s = offset;
 	v = PAGE_OFFSET + s;
 	p = memstart_addr + s;
 	for (; s < top; s += PAGE_SIZE) {
-		ktext = ((char *)v >= _stext && (char *)v < etext) ||
-			((char *)v >= _sinittext && (char *)v < _einittext);
+		ktext = (is_kernel_text(v) || is_kernel_inittext(v));
 		map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL);
 		v += PAGE_SIZE;
 		p += PAGE_SIZE;
-- 
2.26.2

[PATCH v3 6/9] sections: Provide internal __is_kernel() and __is_kernel_text() helper

Message details and related content
An internal __is_kernel() helper which only check the kernel address ranges,
and an internal __is_kernel_text() helper which only check text section ranges.

Signed-off-by: Kefeng Wang <redacted>
---
 include/asm-generic/sections.h | 29 +++++++++++++++++++++++++++++
 include/linux/kallsyms.h       |  4 ++--
 2 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index 811583ca8bd0..a7abeadddc7a 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -186,4 +186,33 @@ static inline bool is_kernel_inittext(unsigned long addr)
 	       addr < (unsigned long)_einittext;
 }
 
+/**
+ * __is_kernel_text - checks if the pointer address is located in the
+ *                    .text section
+ *
+ * @addr: address to check
+ *
+ * Returns: true if the address is located in .text, false otherwise.
+ * Note: an internal helper, only check the range of _stext to _etext.
+ */
+static inline bool __is_kernel_text(unsigned long addr)
+{
+	return addr >= (unsigned long)_stext &&
+	       addr < (unsigned long)_etext;
+}
+
+/**
+ * __is_kernel - checks if the pointer address is located in the kernel range
+ *
+ * @addr: address to check
+ *
+ * Returns: true if the address is located in the kernel range, false otherwise.
+ * Note: an internal helper, only check the range of _stext to _end.
+ */
+static inline bool __is_kernel(unsigned long addr)
+{
+	return addr >= (unsigned long)_stext &&
+	       addr < (unsigned long)_end;
+}
+
 #endif /* _ASM_GENERIC_SECTIONS_H_ */
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 8a9d329c927c..5fb17dd4b6fa 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -26,14 +26,14 @@ struct module;
 
 static inline int is_kernel_text(unsigned long addr)
 {
-	if ((addr >= (unsigned long)_stext && addr < (unsigned long)_etext))
+	if (__is_kernel_text(addr))
 		return 1;
 	return in_gate_area_no_mm(addr);
 }
 
 static inline int is_kernel(unsigned long addr)
 {
-	if (addr >= (unsigned long)_stext && addr < (unsigned long)_end)
+	if (__is_kernel(addr))
 		return 1;
 	return in_gate_area_no_mm(addr);
 }
-- 
2.26.2

Re: [PATCH v3 9/9] powerpc/mm: Use is_kernel_text() and is_kernel_inittext() helper

Message details and related content

Le 26/09/2021 à 09:20, Kefeng Wang a écrit :
quoted hunk
Use is_kernel_text() and is_kernel_inittext() helper to simplify code,
also drop etext, _stext, _sinittext, _einittext declaration which
already declared in section.h.

Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <redacted>
Cc: <redacted>
Signed-off-by: Kefeng Wang <redacted>
---
  arch/powerpc/mm/pgtable_32.c | 7 ++-----
  1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index dcf5ecca19d9..13c798308c2e 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -33,8 +33,6 @@
  
  #include <mm/mmu_decl.h>
  
-extern char etext[], _stext[], _sinittext[], _einittext[];
-
  static u8 early_fixmap_pagetable[FIXMAP_PTE_SIZE] __page_aligned_data;
  
  notrace void __init early_ioremap_init(void)
@@ -104,14 +102,13 @@ static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
  {
  	unsigned long v, s;
  	phys_addr_t p;
-	int ktext;
+	bool ktext;
  
  	s = offset;
  	v = PAGE_OFFSET + s;
  	p = memstart_addr + s;
  	for (; s < top; s += PAGE_SIZE) {
-		ktext = ((char *)v >= _stext && (char *)v < etext) ||
-			((char *)v >= _sinittext && (char *)v < _einittext);
+		ktext = (is_kernel_text(v) || is_kernel_inittext(v));
I think we could use core_kernel_next() instead.

  		map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL);
  		v += PAGE_SIZE;
  		p += PAGE_SIZE;



Build failure on mpc885_ads_defconfig

arch/powerpc/mm/pgtable_32.c: In function '__mapin_ram_chunk':
arch/powerpc/mm/pgtable_32.c:111:26: error: implicit declaration of function 'is_kernel_text'; did you mean 'is_kernel_inittext'? [-Werror=implicit-function-declaration]
  111 |                 ktext = (is_kernel_text(v) || is_kernel_inittext(v));
      |                          ^~~~~~~~~~~~~~
      |                          is_kernel_inittext
cc1: all warnings being treated as errors
make[2]: *** [scripts/Makefile.build:277: arch/powerpc/mm/pgtable_32.o] Error 1
make[1]: *** [scripts/Makefile.build:540: arch/powerpc/mm] Error 2
make: *** [Makefile:1868: arch/powerpc] Error 2

Re: [PATCH v3 9/9] powerpc/mm: Use is_kernel_text() and is_kernel_inittext() helper

Message details and related content

On 2021/9/29 1:51, Christophe Leroy wrote:

Le 26/09/2021 à 09:20, Kefeng Wang a écrit :
quoted
Use is_kernel_text() and is_kernel_inittext() helper to simplify code,
also drop etext, _stext, _sinittext, _einittext declaration which
already declared in section.h.

Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <redacted>
Cc: <redacted>
Signed-off-by: Kefeng Wang <redacted>
---
  arch/powerpc/mm/pgtable_32.c | 7 ++-----
  1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index dcf5ecca19d9..13c798308c2e 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -33,8 +33,6 @@
  #include <mm/mmu_decl.h>
-extern char etext[], _stext[], _sinittext[], _einittext[];
-
  static u8 early_fixmap_pagetable[FIXMAP_PTE_SIZE] __page_aligned_data;
  notrace void __init early_ioremap_init(void)
@@ -104,14 +102,13 @@ static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
  {
      unsigned long v, s;
      phys_addr_t p;
-    int ktext;
+    bool ktext;
      s = offset;
      v = PAGE_OFFSET + s;
      p = memstart_addr + s;
      for (; s < top; s += PAGE_SIZE) {
-        ktext = ((char *)v >= _stext && (char *)v < etext) ||
-            ((char *)v >= _sinittext && (char *)v < _einittext);
+        ktext = (is_kernel_text(v) || is_kernel_inittext(v));

1 more quoted lines

Indead. oops, sorry for the build error, will update, thanks.
Build failure on mpc885_ads_defconfig

arch/powerpc/mm/pgtable_32.c: In function '__mapin_ram_chunk':
arch/powerpc/mm/pgtable_32.c:111:26: error: implicit declaration of function 'is_kernel_text'; did you mean 'is_kernel_inittext'? [-Werror=implicit-function-declaration]
   111 |                 ktext = (is_kernel_text(v) || is_kernel_inittext(v));
       |                          ^~~~~~~~~~~~~~
       |                          is_kernel_inittext
cc1: all warnings being treated as errors
make[2]: *** [scripts/Makefile.build:277: arch/powerpc/mm/pgtable_32.o] Error 1
make[1]: *** [scripts/Makefile.build:540: arch/powerpc/mm] Error 2
make: *** [Makefile:1868: arch/powerpc] Error 2


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