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arch/arm64: .bss initialization using assembly language

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The compiler will optimize boot_early_memset to memset,
but memset in libc cannot be used before MMU is enabled.
Therefore, assembly language is used to implement the
initialization of bss to avoid this problem.

Signed-off-by: zhangyuan21 <zhangyuan21@xiaomi.com>
This commit is contained in:
zhangyuan21 2023-05-11 22:57:26 +08:00 committed by Brennan Ashton
parent 3493ea399f
commit 36acd4fce5
2 changed files with 37 additions and 16 deletions
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16
arch/arm64/src/common/arm64_boot.c
View File

@ -174,24 +174,8 @@ void arm64_boot_el1_init(void)
ARM64_ISB();
}
/* These simple memset alternatives are necessary
* as the function at libc is depend on the MMU
* to be active.
*/
static void boot_early_memset(void *dst, int c, size_t n)
{
uint8_t *d = dst;
while (n--)
{
*d++ = c;
}
}
void arm64_boot_primary_c_routine(void)
{
boot_early_memset(_START_BSS, 0, _END_BSS - _START_BSS);
arm64_chip_boot();
up_perf_init(NULL);
nx_start();

37
arch/arm64/src/common/arm64_head.S
View File

@ -212,6 +212,8 @@ primary_core:
bl arm64_earlyprintinit
#endif
bl arm64_data_initialize
PRINT(primary_boot, "- Ready to Boot Primary CPU\r\n")
cpu_boot:
@ -351,3 +353,38 @@ boot_stage_puts:
.type boot_low_puts, %function;
#endif /* !CONFIG_ARCH_EARLY_PRINT */
/***************************************************************************
* Name: arm64_data_initialize
***************************************************************************/
.type arm64_data_initialize, #function
arm64_data_initialize:
/* Zero BSS */
adr x0, .Linitparms
ldp x1, x2, [x0], #8
mov x0, #0
1:
cmp x1, x2
bge 2f
str x0, [x1], #8
b 1b
2:
ret
.size arm64_data_initialize, . - arm64_data_initialize
/***************************************************************************
* Text-section constants
***************************************************************************/
.data
.align 8
.type .Linitparms, %object
.Linitparms:
.quad _sbss
.quad _ebss
.size .Linitparms, . -.Linitparms