Bo Gan 4c1c77e085 include: riscv_asm: Optimize csr_xyz() macros to reduce stack usage ...

When using debug builds, aka., DEBUG=1, csr_write_num() function can
trigger stack overflow. This is caused by the large amount of macro
expansion of csr_write(...), which, under debug builds, will generate
massive amount of stack variables (tested with GCC 13.2.0). The issue
is masked previously as we didn't have too many csr_write()'s before
commit 55296fd27c, but now, it does overflow the default 4KB stack.

The csr_read(relaxed) macros already use the "register" modifier to
optimize stack usage (perhaps unknowingly?), so this patch just
follows suit.

Fixes: 55296fd27c ("lib: Allow custom CSRs in csr_read_num() and csr_write_num()")
Signed-off-by: Bo Gan <ganboing@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20251216052528.18896-1-ganboing@gmail.com
Signed-off-by: Anup Patel <anup@brainfault.org>

2025-12-27 11:21:27 +05:30

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