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
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
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
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
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
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 */
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)
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
#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
/*
* 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;
}
}
#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 += <some size>'. 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;
}
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
projects / u-boot / commitdiff