From: Albert ARIBAUD Date: Wed, 25 Nov 2015 16:56:32 +0000 (+0100) Subject: Fix board init code to respect the C runtime environment X-Git-Tag: v2016.03-rc1~334 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=ecc3066;p=oweals%2Fu-boot.git Fix board init code to respect the C runtime environment board_init_f_mem() alters the C runtime environment's stack it is actually already using. This is not a valid behaviour within a C runtime environment. Split board_init_f_mem into C functions which do not alter their own stack and always behave properly with respect to their C runtime environment. Signed-off-by: Albert ARIBAUD Acked-by: Thomas Chou --- diff --git a/arch/arc/lib/start.S b/arch/arc/lib/start.S index 26a5934189..90ee7e0fe4 100644 --- a/arch/arc/lib/start.S +++ b/arch/arc/lib/start.S @@ -50,18 +50,20 @@ ENTRY(_start) 1: #endif - /* Setup stack- and frame-pointers */ + /* Establish C runtime stack and frame */ mov %sp, CONFIG_SYS_INIT_SP_ADDR mov %fp, %sp - /* Allocate and zero GD, update SP */ + /* Allocate reserved area from current top of stack */ mov %r0, %sp - bl board_init_f_mem - - /* Update stack- and frame-pointers */ + bl board_init_f_alloc_reserve + /* Set stack below reserved area, adjust frame pointer accordingly */ mov %sp, %r0 mov %fp, %sp + /* Initialize reserved area - note: r0 already contains address */ + bl board_init_f_init_reserve + /* Zero the one and only argument of "board_init_f" */ mov_s %r0, 0 j board_init_f diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S index 80548ebbf6..4f2a7121c4 100644 --- a/arch/arm/lib/crt0.S +++ b/arch/arm/lib/crt0.S @@ -83,8 +83,9 @@ ENTRY(_main) bic sp, sp, #7 /* 8-byte alignment for ABI compliance */ #endif mov r0, sp - bl board_init_f_mem + bl board_init_f_alloc_reserve mov sp, r0 + bl board_init_f_init_reserve mov r0, #0 bl board_init_f diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S index cef1c7171c..b4fc760609 100644 --- a/arch/arm/lib/crt0_64.S +++ b/arch/arm/lib/crt0_64.S @@ -75,8 +75,10 @@ ENTRY(_main) ldr x0, =(CONFIG_SYS_INIT_SP_ADDR) #endif bic sp, x0, #0xf /* 16-byte alignment for ABI compliance */ - bl board_init_f_mem + mov x0, sp + bl board_init_f_alloc_reserve mov sp, x0 + bl board_init_f_init_reserve mov x0, #0 bl board_init_f diff --git a/arch/microblaze/cpu/start.S b/arch/microblaze/cpu/start.S index 14f46a8f04..206be3e3ee 100644 --- a/arch/microblaze/cpu/start.S +++ b/arch/microblaze/cpu/start.S @@ -25,7 +25,7 @@ _start: addi r8, r0, __end mts rslr, r8 - /* TODO: Redo this code to call board_init_f_mem() */ + /* TODO: Redo this code to call board_init_f_*() */ #if defined(CONFIG_SPL_BUILD) addi r1, r0, CONFIG_SPL_STACK_ADDR mts rshr, r1 @@ -142,7 +142,7 @@ _start: ori r12, r12, 0x1a0 mts rmsr, r12 - /* TODO: Redo this code to call board_init_f_mem() */ + /* TODO: Redo this code to call board_init_f_*() */ clear_bss: /* clear BSS segments */ addi r5, r0, __bss_start diff --git a/arch/nios2/cpu/start.S b/arch/nios2/cpu/start.S index 54787c53ca..204d0cd9d4 100644 --- a/arch/nios2/cpu/start.S +++ b/arch/nios2/cpu/start.S @@ -106,14 +106,18 @@ _reloc: stw r0, 4(sp) mov fp, sp - /* Allocate and zero GD, update SP */ + /* Allocate and initialize reserved area, update SP */ mov r4, sp - movhi r2, %hi(board_init_f_mem@h) - ori r2, r2, %lo(board_init_f_mem@h) + movhi r2, %hi(board_init_f_alloc_reserve@h) + ori r2, r2, %lo(board_init_f_alloc_reserve@h) callr r2 - - /* Update stack- and frame-pointers */ mov sp, r2 + mov r4, sp + movhi r2, %hi(board_init_f_init_reserve@h) + ori r2, r2, %lo(board_init_f_init_reserve@h) + callr r2 + + /* Update frame-pointer */ mov fp, sp /* Call board_init_f -- never returns */ diff --git a/arch/powerpc/cpu/ppc4xx/start.S b/arch/powerpc/cpu/ppc4xx/start.S index 3dd0557aa6..137afce37a 100644 --- a/arch/powerpc/cpu/ppc4xx/start.S +++ b/arch/powerpc/cpu/ppc4xx/start.S @@ -762,8 +762,9 @@ _start: bl cpu_init_f /* run low-level CPU init code (from Flash) */ #ifdef CONFIG_SYS_GENERIC_BOARD mr r3, r1 - bl board_init_f_mem + bl board_init_f_alloc_reserve mr r1, r3 + bl board_init_f_init_reserve li r0,0 stwu r0, -4(r1) stwu r0, -4(r1) @@ -1038,8 +1039,9 @@ _start: bl cpu_init_f /* run low-level CPU init code (from Flash) */ #ifdef CONFIG_SYS_GENERIC_BOARD mr r3, r1 - bl board_init_f_mem + bl board_init_f_alloc_reserve mr r1, r3 + bl board_init_f_init_reserve stwu r0, -4(r1) stwu r0, -4(r1) #endif diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S index 5b4ee79d88..485868ff57 100644 --- a/arch/x86/cpu/start.S +++ b/arch/x86/cpu/start.S @@ -123,8 +123,9 @@ car_init_ret: #endif /* Set up global data */ mov %esp, %eax - call board_init_f_mem + call board_init_f_alloc_reserve mov %eax, %esp + call board_init_f_init_reserve #ifdef CONFIG_DEBUG_UART call debug_uart_init diff --git a/arch/x86/lib/fsp/fsp_common.c b/arch/x86/lib/fsp/fsp_common.c index 5276ce6ab1..8479af1d7e 100644 --- a/arch/x86/lib/fsp/fsp_common.c +++ b/arch/x86/lib/fsp/fsp_common.c @@ -90,8 +90,8 @@ int x86_fsp_init(void) /* * The second time we enter here, adjust the size of malloc() * pool before relocation. Given gd->malloc_base was adjusted - * after the call to board_init_f_mem() in arch/x86/cpu/start.S, - * we should fix up gd->malloc_limit here. + * after the call to board_init_f_init_reserve() in arch/x86/ + * cpu/start.S, we should fix up gd->malloc_limit here. */ gd->malloc_limit += CONFIG_FSP_SYS_MALLOC_F_LEN; } diff --git a/common/init/board_init.c b/common/init/board_init.c index 1c6126d8ce..e649e078b9 100644 --- a/common/init/board_init.c +++ b/common/init/board_init.c @@ -29,31 +29,120 @@ __weak void arch_setup_gd(struct global_data *gd_ptr) } #endif /* !CONFIG_X86 */ -ulong board_init_f_mem(ulong top) +/* + * Allocate reserved space for use as 'globals' from 'top' address and + * return 'bottom' address of allocated space + * + * Notes: + * + * Actual reservation cannot be done from within this function as + * it requires altering the C stack pointer, so this will be done by + * the caller upon return from this function. + * + * IMPORTANT: + * + * Alignment constraints may differ for each 'chunk' allocated. For now: + * + * - GD is aligned down on a 16-byte boundary + * + * - the early malloc arena is not aligned, therefore it follows the stack + * alignment constraint of the architecture for which we are bulding. + * + * - GD is allocated last, so that the return value of this functions is + * both the bottom of the reserved area and the address of GD, should + * the calling context need it. + */ + +ulong board_init_f_alloc_reserve(ulong top) +{ + /* Reserve early malloc arena */ +#if defined(CONFIG_SYS_MALLOC_F) + top -= CONFIG_SYS_MALLOC_F_LEN; +#endif + /* LAST : reserve GD (rounded up to a multiple of 16 bytes) */ + top = rounddown(top-sizeof(struct global_data), 16); + + return top; +} + +/* + * Initialize reserved space (which has been safely allocated on the C + * stack from the C runtime environment handling code). + * + * Notes: + * + * Actual reservation was done by the caller; the locations from base + * to base+size-1 (where 'size' is the value returned by the allocation + * function above) can be accessed freely without risk of corrupting the + * C runtime environment. + * + * IMPORTANT: + * + * Upon return from the allocation function above, on some architectures + * the caller will set gd to the lowest reserved location. Therefore, in + * this initialization function, the global data MUST be placed at base. + * + * ALSO IMPORTANT: + * + * On some architectures, gd will already be good when entering this + * function. On others, it will only be good once arch_setup_gd() returns. + * Therefore, global data accesses must be done: + * + * - through gd_ptr if before the call to arch_setup_gd(); + * + * - through gd once arch_setup_gd() has been called. + * + * Do not use 'gd->' until arch_setup_gd() has been called! + * + * IMPORTANT TOO: + * + * Initialization for each "chunk" (GD, early malloc arena...) ends with + * an incrementation line of the form 'base += '. The last of + * these incrementations seems useless, as base will not be used any + * more after this incrementation; but if/when a new "chunk" is appended, + * this increment will be essential as it will give base right value for + * this new chunk (which will have to end with its own incrementation + * statement). Besides, the compiler's optimizer will silently detect + * and remove the last base incrementation, therefore leaving that last + * (seemingly useless) incrementation causes no code increase. + */ + +void board_init_f_init_reserve(ulong base) { struct global_data *gd_ptr; #ifndef _USE_MEMCPY int *ptr; #endif - /* Leave space for the stack we are running with now */ - top -= 0x40; + /* + * clear GD entirely and set it up. + * Use gd_ptr, as gd may not be properly set yet. + */ - top -= sizeof(struct global_data); - top = ALIGN(top, 16); - gd_ptr = (struct global_data *)top; + gd_ptr = (struct global_data *)base; + /* zero the area */ #ifdef _USE_MEMCPY memset(gd_ptr, '\0', sizeof(*gd)); #else for (ptr = (int *)gd_ptr; ptr < (int *)(gd_ptr + 1); ) *ptr++ = 0; #endif + /* set GD unless architecture did it already */ +#ifndef CONFIG_X86 arch_setup_gd(gd_ptr); +#endif + /* next alloc will be higher by one GD plus 16-byte alignment */ + base += roundup(sizeof(struct global_data), 16); + + /* + * record early malloc arena start. + * Use gd as it is now properly set for all architectures. + */ #if defined(CONFIG_SYS_MALLOC_F) - top -= CONFIG_SYS_MALLOC_F_LEN; - gd->malloc_base = top; + /* go down one 'early malloc arena' */ + gd->malloc_base = base; + /* next alloc will be higher by one 'early malloc arena' size */ + base += CONFIG_SYS_MALLOC_F_LEN; #endif - - return top; } diff --git a/include/common.h b/include/common.h index 75c78d5ac2..7bed0cc0d1 100644 --- a/include/common.h +++ b/include/common.h @@ -224,32 +224,26 @@ void board_init_f(ulong); void board_init_r(gd_t *, ulong) __attribute__ ((noreturn)); /** - * board_init_f_mem() - Allocate global data and set stack position + * ulong board_init_f_alloc_reserve - allocate reserved area * * This function is called by each architecture very early in the start-up - * code to set up the environment for board_init_f(). It allocates space for - * global_data (see include/asm-generic/global_data.h) and places the stack - * below this. + * code to allow the C runtime to reserve space on the stack for writable + * 'globals' such as GD and the malloc arena. * - * This function requires a stack[1] Normally this is at @top. The function - * starts allocating space from 64 bytes below @top. First it creates space - * for global_data. Then it calls arch_setup_gd() which sets gd to point to - * the global_data space and can reserve additional bytes of space if - * required). Finally it allocates early malloc() memory - * (CONFIG_SYS_MALLOC_F_LEN). The new top of the stack is just below this, - * and it returned by this function. + * @top: top of the reserve area, growing down. + * @return: bottom of reserved area + */ +ulong board_init_f_alloc_reserve(ulong top); + +/** + * board_init_f_init_reserve - initialize the reserved area(s) * - * [1] Strictly speaking it would be possible to implement this function - * in C on many archs such that it does not require a stack. However this - * does not seem hugely important as only 64 byte are wasted. The 64 bytes - * are used to handle the calling standard which generally requires pushing - * addresses or registers onto the stack. We should be able to get away with - * less if this becomes important. + * This function is called once the C runtime has allocated the reserved + * area on the stack. It must initialize the GD at the base of that area. * - * @top: Top of available memory, also normally the top of the stack - * @return: New stack location + * @base: top from which reservation was done */ -ulong board_init_f_mem(ulong top); +void board_init_f_init_reserve(ulong base); /** * arch_setup_gd() - Set up the global_data pointer