On Sun, Dec 01, 2024 at 08:28:05AM -0700, Simon Glass wrote:
The reserve_stack_aligned() function already ensures that the resulting address is aligned to a 16-byte boundary. The comment seems to suggest that 16 is passed reserve_stack_aligned() to make it aligned.
Change the value to 0, since the stack can start at the current address, if it is suitably aligned already.
Signed-off-by: Simon Glass sjg@chromium.org
Er: /* * reserve after start_addr_sp the requested size and make the stack pointer * 16-byte aligned, this alignment is needed for cast on the reserved memory * ref = x86_64 ABI: https://reviews.llvm.org/D30049: 16 bytes * = ARMv8 Instruction Set Overview: quad word, 16 bytes */ static unsigned long reserve_stack_aligned(size_t size) { return ALIGN_DOWN(gd->start_addr_sp - size, 16); }
is what the code is today.
(no changes since v1)
common/board_f.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/common/board_f.c b/common/board_f.c index 98dc2591e1d..677e37d93c0 100644 --- a/common/board_f.c +++ b/common/board_f.c @@ -601,7 +601,7 @@ __weak int arch_reserve_stacks(void) static int reserve_stacks(void) { /* make stack pointer 16-byte aligned */
- gd->start_addr_sp = reserve_stack_aligned(16);
gd->start_addr_sp = reserve_stack_aligned(0);
/*
- let the architecture-specific code tailor gd->start_addr_sp and
And this is the last call to reserve_stack_aligned(). So, this is going to save us between 16 and 0 bytes of memory. If we're going to make a change here we need to comment in the code more what we're up to at this point, and the commit message should be more authoritatively worded too.