x86: use z_bss_zero and z_data_copy

Instead of doing these in assembly, use the common z_bss_zero()
and z_data_copy() C functions instead. This simplifies code
a bit and we won't miss any additions to these two functions
(if any) under x86 in the future (as x86_64 was actually not
clearing gcov bss area).

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
This commit is contained in:
Daniel Leung 2021-02-10 14:31:20 -08:00 committed by Anas Nashif
commit c0ee8c4a43
3 changed files with 19 additions and 115 deletions

View file

@ -25,6 +25,8 @@
/* externs */
GTEXT(z_x86_prep_c)
GTEXT(z_bss_zero)
GTEXT(z_data_copy)
GDATA(_idt_base_address)
GDATA(z_interrupt_stacks)
@ -152,42 +154,17 @@ __csSet:
addl $CONFIG_ISR_STACK_SIZE, %esp
#endif
/* Clear BSS */
call z_bss_zero
#ifdef CONFIG_XIP
/*
* copy DATA section from ROM to RAM region
* DATA is followed by BSS section.
*/
movl $__data_ram_start, %edi /* DATA in RAM (dest) */
movl $__data_rom_start, %esi /* DATA in ROM (src) */
movl $__data_num_words, %ecx /* Size of DATA in quad bytes */
call _x86_data_copy
#ifdef CONFIG_USERSPACE
movl $_app_smem_start, %edi /* DATA in RAM (dest) */
movl $_app_smem_rom_start, %esi /* DATA in ROM (src) */
movl $_app_smem_num_words, %ecx /* Size of DATA in quad bytes */
call _x86_data_copy
#endif /* CONFIG_USERSPACE */
#endif /* CONFIG_XIP */
/*
* Clear BSS: bzero (__bss_start, __bss_num_words*4)
/* Copy data from flash to RAM.
*
* It's assumed that BSS size will be a multiple of a long (4 bytes),
* and aligned on a double word (32-bit) boundary
* This is a must is CONFIG_GDT_DYNAMIC is enabled,
* as _gdt needs to be in RAM.
*/
movl $__bss_start, %edi /* load BSS start address */
movl $__bss_num_words, %ecx /* number of quad bytes in .bss */
call _x86_bss_zero
#ifdef CONFIG_COVERAGE_GCOV
movl $__gcov_bss_start, %edi /* load gcov BSS start address */
movl $__gcov_bss_num_words, %ecx /* number of quad bytes */
call _x86_bss_zero
#endif /* CONFIG_COVERAGE_GCOV */
call z_data_copy
#endif
#ifdef CONFIG_GDT_DYNAMIC
/* activate RAM-based Global Descriptor Table (GDT) */
@ -227,70 +204,6 @@ __csSet:
pushl %ebx /* pointer to multiboot info, or NULL */
call z_x86_prep_c /* enter kernel; never returns */
_x86_bss_zero:
/* ECX = size, EDI = starting address */
#ifdef CONFIG_X86_SSE
/* use XMM register to clear 16 bytes at a time */
pxor %xmm0, %xmm0 /* zero out xmm0 register */
movl %ecx, %edx /* make a copy of # quad bytes */
shrl $2, %ecx /* How many multiples of 16 byte ? */
je bssWords
bssDQ:
movdqu %xmm0, (%edi) /* zero 16 bytes... */
addl $16, %edi
loop bssDQ
/* fall through to handle the remaining double words (32-bit chunks) */
bssWords:
xorl %eax, %eax /* fill memory with 0 */
movl %edx, %ecx /* move # quad bytes into ECX (for rep) */
andl $0x3, %ecx /* only need to zero at most 3 quad bytes */
cld
rep
stosl /* zero memory per 4 bytes */
#else /* !CONFIG_X86_SSE */
/* clear out BSS double words (32-bits at a time) */
xorl %eax, %eax /* fill memory with 0 */
cld
rep
stosl /* zero memory per 4 bytes */
#endif /* CONFIG_X86_SSE */
ret
#ifdef CONFIG_XIP
_x86_data_copy:
/* EDI = dest, ESI = source, ECX = size in 32-bit chunks */
#ifdef CONFIG_X86_SSE
/* copy 16 bytes at a time using XMM until < 16 bytes remain */
movl %ecx ,%edx /* save number of quad bytes */
shrl $2, %ecx /* How many 16 bytes? */
je dataWords
dataDQ:
movdqu (%esi), %xmm0
movdqu %xmm0, (%edi)
addl $16, %esi
addl $16, %edi
loop dataDQ
dataWords:
movl %edx, %ecx /* restore # quad bytes */
andl $0x3, %ecx /* only need to copy at most 3 quad bytes */
#endif /* CONFIG_X86_SSE */
rep
movsl /* copy data 4 bytes at a time */
ret
#endif /* CONFIG_XIP */
#if defined(CONFIG_X86_SSE)
/* SSE control & status register initial value */

View file

@ -163,19 +163,18 @@ FUNC_NORETURN void z_x86_cpu_init(struct x86_cpuboot *cpuboot)
{
x86_sse_init(NULL);
#if CONFIG_MP_NUM_CPUS > 1
/* The internal cpu_number is the index to x86_cpuboot[] */
unsigned char cpu_num = (unsigned char)(cpuboot - x86_cpuboot);
if (cpu_num > 0) {
/*
* For CPU #0, z_loapic_enable(0) will be done
* inside z_x86_prep_c() so there is no need to do it
* here.
*/
z_loapic_enable(cpu_num);
}
if (cpu_num == 0) {
/* Only need to do these once per boot */
z_bss_zero();
#ifdef CONFIG_XIP
z_data_copy();
#endif
}
z_loapic_enable(cpu_num);
#ifdef CONFIG_USERSPACE
/* Set landing site for 'syscall' instruction */

View file

@ -148,16 +148,8 @@ __start:
/*
* N.B.: if multiboot info struct is present, "common.S"
* has left a pointer to it in EBX. do not clobber (yet).
*
* next, clear the BSS. note we're still in 32-bit mode,
* so the BSS must fit entirely in the first 4GB of RAM.
* has left a pointer to it in EBX.
*/
cld
xorl %eax, %eax
movl $__bss_start, %edi
movl $__bss_num_dwords, %ecx
rep stosl
movl $x86_cpuboot, %ebp /* BSP is always logical CPU id 0 */
movl %ebx, __x86_cpuboot_t_arg_OFFSET(%ebp) /* multiboot info */