Commit ecc30663 authored by Albert ARIBAUD's avatar Albert ARIBAUD Committed by Tom Rini

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: default avatarAlbert ARIBAUD <albert.u.boot@aribaud.net>
Acked-by: default avatarThomas Chou <thomas@wytron.com.tw>
parent 20d08f59
......@@ -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
......
......@@ -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
......
......@@ -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
......
......@@ -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
......
......@@ -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 */
......
......@@ -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
......
......@@ -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
......
......@@ -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;
}
......
......@@ -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 += <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;
}
......@@ -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
......
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