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[PATCH] xen/ACPI: Use const char * for string literals

Andrew Cooper posted 1 patch 1 year, 4 months ago
Patches applied successfully (tree, apply log)
git fetch https://gitlab.com/xen-project/patchew/xen tags/patchew/20230714131026.3082591-1-andrew.cooper3@citrix.com
xen/drivers/acpi/tables.c           |  6 +++---
xen/drivers/acpi/tables/tbfadt.c    |  2 +-
xen/drivers/acpi/tables/tbutils.c   |  2 +-
xen/drivers/acpi/utilities/utmisc.c |  6 +++---
xen/include/acpi/actables.h         |  2 +-
xen/include/acpi/acutils.h          | 12 ++++++------
xen/include/xen/acpi.h              |  6 +++---
7 files changed, 18 insertions(+), 18 deletions(-)
[PATCH] xen/ACPI: Use const char * for string literals
Posted by Andrew Cooper 1 year, 4 months ago 
For pre-ANSI-C compatibility reasons, string literals have a mutable type, but
it is undefined behaviour to mutate them.

Swap char *'s to const char *'s for variables which hold string literals.

This fixes several violations of MISRA Rule 7.4:

  A string literal shall not be assigned to an object unless the object's type
  is "pointer to const-qualified char".

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: George Dunlap <George.Dunlap@eu.citrix.com>
CC: Jan Beulich <JBeulich@suse.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Wei Liu <wl@xen.org>
CC: Julien Grall <julien@xen.org>
CC: Roberto Bagnara <roberto.bagnara@bugseng.com>
CC: Nicola Vetrini <nicola.vetrini@bugseng.com>
---
 xen/drivers/acpi/tables.c           |  6 +++---
 xen/drivers/acpi/tables/tbfadt.c    |  2 +-
 xen/drivers/acpi/tables/tbutils.c   |  2 +-
 xen/drivers/acpi/utilities/utmisc.c |  6 +++---
 xen/include/acpi/actables.h         |  2 +-
 xen/include/acpi/acutils.h          | 12 ++++++------
 xen/include/xen/acpi.h              |  6 +++---
 7 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/xen/drivers/acpi/tables.c b/xen/drivers/acpi/tables.c
index 96ff96b84c66..20aed8929b86 100644
--- a/xen/drivers/acpi/tables.c
+++ b/xen/drivers/acpi/tables.c
@@ -300,7 +300,7 @@ acpi_table_get_entry_madt(enum acpi_madt_type entry_id,
 }
 
 int __init
-acpi_parse_entries(char *id, unsigned long table_size,
+acpi_parse_entries(const char *id, unsigned long table_size,
 		   acpi_table_entry_handler handler,
 		   struct acpi_table_header *table_header,
 		   int entry_id, unsigned int max_entries)
@@ -359,7 +359,7 @@ acpi_parse_entries(char *id, unsigned long table_size,
 }
 
 int __init
-acpi_table_parse_entries(char *id,
+acpi_table_parse_entries(const char *id,
 			 unsigned long table_size,
 			 int entry_id,
 			 acpi_table_entry_handler handler,
@@ -405,7 +405,7 @@ acpi_table_parse_madt(enum acpi_madt_type id,
  * Scan the ACPI System Descriptor Table (STD) for a table matching @id,
  * run @handler on it.
  */
-int __init acpi_table_parse(char *id, acpi_table_handler handler)
+int __init acpi_table_parse(const char *id, acpi_table_handler handler)
 {
 	struct acpi_table_header *table = NULL;
 
diff --git a/xen/drivers/acpi/tables/tbfadt.c b/xen/drivers/acpi/tables/tbfadt.c
index d8fcc50deca5..a03836e0dc8a 100644
--- a/xen/drivers/acpi/tables/tbfadt.c
+++ b/xen/drivers/acpi/tables/tbfadt.c
@@ -60,7 +60,7 @@ static void acpi_tb_validate_fadt(void);
 /* Table for conversion of FADT to common internal format and FADT validation */
 
 typedef struct acpi_fadt_info {
-	char *name;
+	const char *name;
 	u16 target;
 	u16 source;
 	u16 length;
diff --git a/xen/drivers/acpi/tables/tbutils.c b/xen/drivers/acpi/tables/tbutils.c
index 11412c47deb4..458989abea99 100644
--- a/xen/drivers/acpi/tables/tbutils.c
+++ b/xen/drivers/acpi/tables/tbutils.c
@@ -243,7 +243,7 @@ u8 acpi_tb_checksum(u8 * buffer, acpi_native_uint length)
 
 void __init
 acpi_tb_install_table(acpi_physical_address address,
-		      u8 flags, char *signature, acpi_native_uint table_index)
+		      u8 flags, const char *signature, acpi_native_uint table_index)
 {
 	struct acpi_table_header *table;
 
diff --git a/xen/drivers/acpi/utilities/utmisc.c b/xen/drivers/acpi/utilities/utmisc.c
index 4e1497ad0fae..ee22c83e3842 100644
--- a/xen/drivers/acpi/utilities/utmisc.c
+++ b/xen/drivers/acpi/utilities/utmisc.c
@@ -134,7 +134,7 @@ const char *__init acpi_ut_validate_exception(acpi_status status)
  ******************************************************************************/
 
 void ACPI_INTERNAL_VAR_XFACE __init
-acpi_ut_error(const char *module_name, u32 line_number, char *format, ...)
+acpi_ut_error(const char *module_name, u32 line_number, const char *format, ...)
 {
 	va_list args;
 
@@ -147,7 +147,7 @@ acpi_ut_error(const char *module_name, u32 line_number, char *format, ...)
 }
 
 void ACPI_INTERNAL_VAR_XFACE __init
-acpi_ut_warning(const char *module_name, u32 line_number, char *format, ...)
+acpi_ut_warning(const char *module_name, u32 line_number, const char *format, ...)
 {
 	va_list args;
 
@@ -161,7 +161,7 @@ acpi_ut_warning(const char *module_name, u32 line_number, char *format, ...)
 }
 
 void ACPI_INTERNAL_VAR_XFACE __init
-acpi_ut_info(const char *module_name, u32 line_number, char *format, ...)
+acpi_ut_info(const char *module_name, u32 line_number, const char *format, ...)
 {
 	va_list args;
 
diff --git a/xen/include/acpi/actables.h b/xen/include/acpi/actables.h
index d4cad35f41c0..527e1c9f9b9d 100644
--- a/xen/include/acpi/actables.h
+++ b/xen/include/acpi/actables.h
@@ -99,7 +99,7 @@ acpi_tb_verify_checksum(struct acpi_table_header *table, u32 length);
 
 void
 acpi_tb_install_table(acpi_physical_address address,
-		      u8 flags, char *signature, acpi_native_uint table_index);
+		      u8 flags, const char *signature, acpi_native_uint table_index);
 
 acpi_status
 acpi_tb_parse_root_table(acpi_physical_address rsdp_address, u8 flags);
diff --git a/xen/include/acpi/acutils.h b/xen/include/acpi/acutils.h
index b1b0df758bd6..ac54adaa8c23 100644
--- a/xen/include/acpi/acutils.h
+++ b/xen/include/acpi/acutils.h
@@ -164,7 +164,7 @@ acpi_ut_debug_print(u32 requested_debug_level,
 		    u32 line_number,
 		    const char *function_name,
 		    const char *module_name,
-		    u32 component_id, char *format, ...) ACPI_PRINTF_LIKE(6);
+		    u32 component_id, const char *format, ...) ACPI_PRINTF_LIKE(6);
 
 void ACPI_INTERNAL_VAR_XFACE
 acpi_ut_debug_print_raw(u32 requested_debug_level,
@@ -172,24 +172,24 @@ acpi_ut_debug_print_raw(u32 requested_debug_level,
 			const char *function_name,
 			const char *module_name,
 			u32 component_id,
-			char *format, ...) ACPI_PRINTF_LIKE(6);
+			const char *format, ...) ACPI_PRINTF_LIKE(6);
 
 void ACPI_INTERNAL_VAR_XFACE
 acpi_ut_error(const char *module_name,
-	      u32 line_number, char *format, ...) ACPI_PRINTF_LIKE(3);
+	      u32 line_number, const char *format, ...) ACPI_PRINTF_LIKE(3);
 
 void ACPI_INTERNAL_VAR_XFACE
 acpi_ut_exception(const char *module_name,
 		  u32 line_number,
-		  acpi_status status, char *format, ...) ACPI_PRINTF_LIKE(4);
+		  acpi_status status, const char *format, ...) ACPI_PRINTF_LIKE(4);
 
 void ACPI_INTERNAL_VAR_XFACE
 acpi_ut_warning(const char *module_name,
-		u32 line_number, char *format, ...) ACPI_PRINTF_LIKE(3);
+		u32 line_number, const char *format, ...) ACPI_PRINTF_LIKE(3);
 
 void ACPI_INTERNAL_VAR_XFACE
 acpi_ut_info(const char *module_name,
-	     u32 line_number, char *format, ...) ACPI_PRINTF_LIKE(3);
+	     u32 line_number, const char *format, ...) ACPI_PRINTF_LIKE(3);
 
 /*
  * utmisc
diff --git a/xen/include/xen/acpi.h b/xen/include/xen/acpi.h
index 352f27f6a723..8ec95791726e 100644
--- a/xen/include/xen/acpi.h
+++ b/xen/include/xen/acpi.h
@@ -81,12 +81,12 @@ int erst_init(void);
 void acpi_hest_init(void);
 
 int acpi_table_init (void);
-int acpi_table_parse(char *id, acpi_table_handler handler);
-int acpi_parse_entries(char *id, unsigned long table_size,
+int acpi_table_parse(const char *id, acpi_table_handler handler);
+int acpi_parse_entries(const char *id, unsigned long table_size,
 		       acpi_table_entry_handler handler,
 		       struct acpi_table_header *table_header,
 		       int entry_id, unsigned int max_entries);
-int acpi_table_parse_entries(char *id, unsigned long table_size,
+int acpi_table_parse_entries(const char *id, unsigned long table_size,
 	int entry_id, acpi_table_entry_handler handler, unsigned int max_entries);
 struct acpi_subtable_header *acpi_table_get_entry_madt(enum acpi_madt_type id,
 						      unsigned int entry_index);
-- 
2.30.2
Re: [PATCH] xen/ACPI: Use const char * for string literals
Posted by Jan Beulich 1 year, 4 months ago 
On 14.07.2023 15:10, Andrew Cooper wrote:
> For pre-ANSI-C compatibility reasons, string literals have a mutable type, but
> it is undefined behaviour to mutate them.
> 
> Swap char *'s to const char *'s for variables which hold string literals.
> 
> This fixes several violations of MISRA Rule 7.4:
> 
>   A string literal shall not be assigned to an object unless the object's type
>   is "pointer to const-qualified char".
> 
> No functional change.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Acked-by: Jan Beulich <jbeulich@suse.com>
Re: [PATCH] xen/ACPI: Use const char * for string literals
Posted by Julien Grall 1 year, 4 months ago 
Hi Andrew,

On 14/07/2023 14:10, Andrew Cooper wrote:
> For pre-ANSI-C compatibility reasons, string literals have a mutable type, but
> it is undefined behaviour to mutate them.
> 
> Swap char *'s to const char *'s for variables which hold string literals.
> 
> This fixes several violations of MISRA Rule 7.4:
> 
>    A string literal shall not be assigned to an object unless the object's type
>    is "pointer to const-qualified char".
> 
> No functional change.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>


I had a similar patch in my queue. But never sent as I didn't know 
whether it would be accepted. This was one of the major blocker for 
switching the hypervisor to use const string.

Acked-by: Julien Grall <jgrall@amazon.com>

Cheers,

-- 
Julien Grall

Patchew 2.1-devel-b67e4c2

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