[PATCH] score: Fix TLS support for some code models
Sebastian Huber
sebastian.huber at embedded-brains.de
Thu Sep 14 06:59:00 UTC 2023
Store symbols with an arbitrary absolute address such as _TLS_Size,
_TLS_Alignment, _TLS_Data_size, and _TLS_BSS_size in an object to avoid issues
with some code models.
Update #4953.
---
cpukit/include/rtems/score/tls.h | 120 +++++++++++++++++-------------
cpukit/score/src/tlsallocsize.c | 43 +++++++++--
testsuites/sptests/sptls01/init.c | 4 +-
3 files changed, 108 insertions(+), 59 deletions(-)
diff --git a/cpukit/include/rtems/score/tls.h b/cpukit/include/rtems/score/tls.h
index fa3ee0afa2..8716c5230c 100644
--- a/cpukit/include/rtems/score/tls.h
+++ b/cpukit/include/rtems/score/tls.h
@@ -10,7 +10,7 @@
*/
/*
- * Copyright (C) 2014, 2022 embedded brains GmbH & Co. KG
+ * Copyright (C) 2014, 2023 embedded brains GmbH & Co. KG
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -59,31 +59,51 @@ extern "C" {
* @{
*/
-extern char _TLS_Data_begin[];
-
-extern char _TLS_Data_end[];
+/**
+ * @brief Represents the TLS configuration.
+ */
+typedef struct {
+ /**
+ * @brief This member is initialized to _TLS_Data_begin.
+ */
+ const char *data_begin;
-extern char _TLS_Data_size[];
+ /**
+ * @brief This member is initialized to _TLS_Data_size.
+ */
+ const char *data_size;
-extern char _TLS_BSS_begin[];
+ /**
+ * @brief This member is initialized to _TLS_BSS_begin.
+ */
+ const char *bss_begin;
-extern char _TLS_BSS_end[];
+ /**
+ * @brief This member is initialized to _TLS_BSS_size.
+ */
+ const char *bss_size;
-extern char _TLS_BSS_size[];
+ /**
+ * @brief This member is initialized to _TLS_Size.
+ */
+ const char *size;
-extern char _TLS_Size[];
+ /**
+ * @brief This member is initialized to _TLS_Alignment.
+ */
+ const char *alignment;
+} TLS_Configuration;
/**
- * @brief The TLS section alignment.
+ * @brief Provides the TLS configuration.
*
- * This symbol is provided by the linker command file as the maximum alignment
- * of the .tdata and .tbss sections. The linker ensures that the first TLS
- * output section is aligned to the maximum alignment of all TLS output
- * sections, see function _bfd_elf_tls_setup() in bfd/elflink.c of the GNU
- * Binutils sources. The linker command file must take into account the case
- * that the .tdata section is empty and the .tbss section is non-empty.
+ * Directly using symbols with an arbitrary absolute address such as
+ * _TLS_Alignment may not work with all code models (for example the AArch64
+ * tiny and small code models). Store the addresses in a read-only object.
+ * Using the volatile qualifier ensures that the compiler actually loads the
+ * address from the object.
*/
-extern char _TLS_Alignment[];
+extern const volatile TLS_Configuration _TLS_Configuration;
typedef struct {
/*
@@ -115,39 +135,25 @@ typedef struct {
uintptr_t offset;
} TLS_Index;
-/**
- * @brief Gets the size of the thread-local storage data in bytes.
- *
- * @return Returns the size of the thread-local storage data in bytes.
- */
-static inline uintptr_t _TLS_Get_size( void )
-{
- uintptr_t size;
-
- /*
- * We must be careful with using _TLS_Size here since this could lead GCC to
- * assume that this symbol is not 0 and the tests for 0 will be optimized
- * away.
- */
- size = (uintptr_t) _TLS_Size;
- RTEMS_OBFUSCATE_VARIABLE( size );
- return size;
-}
-
/**
* @brief Gets the size of the thread control block area in bytes.
*
+ * @param config is the TLS configuration.
+ *
* @return Returns the size of the thread control block area in bytes.
*/
-static inline uintptr_t _TLS_Get_thread_control_block_area_size( void )
+static inline uintptr_t _TLS_Get_thread_control_block_area_size(
+ const volatile TLS_Configuration *config
+)
{
#if CPU_THREAD_LOCAL_STORAGE_VARIANT == 11
uintptr_t alignment;
- alignment = (uintptr_t) _TLS_Alignment;
+ alignment = (uintptr_t) config->alignment;
return RTEMS_ALIGN_UP( sizeof( TLS_Thread_control_block ), alignment );
#else
+ (void) config;
return sizeof( TLS_Thread_control_block );
#endif
}
@@ -163,17 +169,23 @@ uintptr_t _TLS_Get_allocation_size( void );
/**
* @brief Initializes the thread-local storage data.
*
+ * @param config is the TLS configuration.
+ *
* @param[out] tls_data is the thread-local storage data to initialize.
*/
-static inline void _TLS_Copy_and_clear( void *tls_data )
+static inline void _TLS_Copy_and_clear(
+ const volatile TLS_Configuration *config,
+ void *tls_data
+)
{
- tls_data = memcpy( tls_data, _TLS_Data_begin, (uintptr_t) _TLS_Data_size );
+ tls_data =
+ memcpy( tls_data, config->data_begin, (uintptr_t) config->data_size );
memset(
(char *) tls_data +
- (uintptr_t) _TLS_BSS_begin - (uintptr_t) _TLS_Data_begin,
+ (uintptr_t) config->bss_begin - (uintptr_t) config->data_begin,
0,
- (uintptr_t) _TLS_BSS_size
+ (uintptr_t) config->bss_size
);
}
@@ -213,20 +225,22 @@ static inline void _TLS_Initialize_TCB_and_DTV(
*/
static inline void *_TLS_Initialize_area( void *tls_area )
{
- uintptr_t alignment;
- void *tls_data;
- TLS_Thread_control_block *tcb;
- TLS_Dynamic_thread_vector *dtv;
- void *return_value;
+ const volatile TLS_Configuration *config;
+ uintptr_t alignment;
+ void *tls_data;
+ TLS_Thread_control_block *tcb;
+ TLS_Dynamic_thread_vector *dtv;
+ void *return_value;
#if CPU_THREAD_LOCAL_STORAGE_VARIANT == 11
- uintptr_t tcb_size;
+ uintptr_t tcb_size;
#endif
#if CPU_THREAD_LOCAL_STORAGE_VARIANT == 20
- uintptr_t size;
- uintptr_t alignment_2;
+ uintptr_t size;
+ uintptr_t alignment_2;
#endif
- alignment = (uintptr_t) _TLS_Alignment;
+ config = &_TLS_Configuration;
+ alignment = (uintptr_t) config->alignment;
#ifdef __i386__
dtv = NULL;
@@ -249,7 +263,7 @@ static inline void *_TLS_Initialize_area( void *tls_area )
#elif CPU_THREAD_LOCAL_STORAGE_VARIANT == 20
alignment_2 = RTEMS_ALIGN_UP( alignment, CPU_SIZEOF_POINTER );
tls_area = (void *) RTEMS_ALIGN_UP( (uintptr_t) tls_area, alignment_2 );
- size = _TLS_Get_size();
+ size = (uintptr_t) config->size;
tcb = (TLS_Thread_control_block *)
((char *) tls_area + RTEMS_ALIGN_UP( size, alignment_2 ));
tls_data = (char *) tcb - RTEMS_ALIGN_UP( size, alignment );
@@ -259,7 +273,7 @@ static inline void *_TLS_Initialize_area( void *tls_area )
#endif
_TLS_Initialize_TCB_and_DTV( tls_data, tcb, dtv );
- _TLS_Copy_and_clear( tls_data );
+ _TLS_Copy_and_clear( config, tls_data );
return return_value;
}
diff --git a/cpukit/score/src/tlsallocsize.c b/cpukit/score/src/tlsallocsize.c
index f78239192c..fa28391b83 100644
--- a/cpukit/score/src/tlsallocsize.c
+++ b/cpukit/score/src/tlsallocsize.c
@@ -10,7 +10,7 @@
*/
/*
- * Copyright (C) 2014, 2022 embedded brains GmbH & Co. KG
+ * Copyright (C) 2014, 2023 embedded brains GmbH & Co. KG
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -42,14 +42,47 @@
#include <rtems/score/interr.h>
#include <rtems/score/thread.h>
+extern char _TLS_Data_begin[];
+
+extern char _TLS_Data_size[];
+
+extern char _TLS_BSS_begin[];
+
+extern char _TLS_BSS_size[];
+
+extern char _TLS_Size[];
+
+/**
+ * @brief The TLS section alignment.
+ *
+ * This symbol is provided by the linker command file as the maximum alignment
+ * of the .tdata and .tbss sections. The linker ensures that the first TLS
+ * output section is aligned to the maximum alignment of all TLS output
+ * sections, see function _bfd_elf_tls_setup() in bfd/elflink.c of the GNU
+ * Binutils sources. The linker command file must take into account the case
+ * that the .tdata section is empty and the .tbss section is non-empty.
+ */
+extern char _TLS_Alignment[];
+
+const volatile TLS_Configuration _TLS_Configuration = {
+ .data_begin = _TLS_Data_begin,
+ .data_size = _TLS_Data_size,
+ .bss_begin = _TLS_BSS_begin,
+ .bss_size = _TLS_BSS_size,
+ .size = _TLS_Size,
+ .alignment = _TLS_Alignment
+};
+
static uintptr_t _TLS_Allocation_size;
uintptr_t _TLS_Get_allocation_size( void )
{
- uintptr_t size;
- uintptr_t allocation_size;
+ const volatile TLS_Configuration *config;
+ uintptr_t size;
+ uintptr_t allocation_size;
- size = _TLS_Get_size();
+ config = &_TLS_Configuration;
+ size = (uintptr_t) config->size;
if ( size == 0 ) {
return 0;
@@ -66,7 +99,7 @@ uintptr_t _TLS_Get_allocation_size( void )
* shall meet the stack alignment requirement.
*/
stack_align = CPU_STACK_ALIGNMENT;
- tls_align = RTEMS_ALIGN_UP( (uintptr_t) _TLS_Alignment, stack_align );
+ tls_align = RTEMS_ALIGN_UP( (uintptr_t) config->alignment, stack_align );
#ifndef __i386__
/* Reserve space for the dynamic thread vector */
diff --git a/testsuites/sptests/sptls01/init.c b/testsuites/sptests/sptls01/init.c
index acb5d43a5e..5dd49f4702 100644
--- a/testsuites/sptests/sptls01/init.c
+++ b/testsuites/sptests/sptls01/init.c
@@ -67,9 +67,11 @@ static void task(rtems_task_argument arg)
static void check_tls_size(void)
{
+ const volatile TLS_Configuration *config;
uintptr_t tls_size;
- tls_size = _TLS_Get_size();
+ config = &_TLS_Configuration;
+ tls_size = (uintptr_t) config->size;
if (tls_size != 1) {
printk(
--
2.35.3
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