[kvm-unit-tests PATCH v2 04/13] treewide: lib/stack: Make base_address arch specific

[Nicholas Piggin]

On Wed Mar 6, 2024 at 3:09 AM AEST, Andrew Jones wrote:
> Calculating the offset of an address is image specific, which is
> architecture specific. Until now, all architectures and architecture
> configurations which select CONFIG_RELOC were able to subtract
> _etext, but the EFI configuration of riscv cannot (it must subtract
> ImageBase). Make this function weak, such that an architecture may
> override it when necessary, to accommodate the image layout. Then,
> immediately supply the riscv override.
>

Thanks for making these changes. Looks good. For the generic parts,

Reviewed-by: Nicholas Piggin <npiggin at gmail.com>

Thanks,
Nick

> Signed-off-by: Andrew Jones <andrew.jones at linux.dev>
> ---
>  lib/riscv/stack.c | 18 ++++++++++++++++++
>  lib/stack.c       |  8 ++++----
>  lib/stack.h       |  2 ++
>  3 files changed, 24 insertions(+), 4 deletions(-)
>
> diff --git a/lib/riscv/stack.c b/lib/riscv/stack.c
> index d865594b9671..2cd7f012738b 100644
> --- a/lib/riscv/stack.c
> +++ b/lib/riscv/stack.c
> @@ -2,6 +2,24 @@
>  #include <libcflat.h>
>  #include <stack.h>
>  
> +#ifdef CONFIG_RELOC
> +extern char ImageBase, _text, _etext;
> +
> +bool arch_base_address(const void *rebased_addr, unsigned long *addr)
> +{
> +	unsigned long ra = (unsigned long)rebased_addr;
> +	unsigned long base = (unsigned long)&ImageBase;
> +	unsigned long start = (unsigned long)&_text;
> +	unsigned long end = (unsigned long)&_etext;
> +
> +	if (ra < start || ra >= end)
> +		return false;
> +
> +	*addr = ra - base;
> +	return true;
> +}
> +#endif
> +
>  int arch_backtrace_frame(const void *frame, const void **return_addrs,
>  			 int max_depth, bool current_frame)
>  {
> diff --git a/lib/stack.c b/lib/stack.c
> index dd6bfa8dac6e..086fec544a81 100644
> --- a/lib/stack.c
> +++ b/lib/stack.c
> @@ -14,7 +14,7 @@
>  #ifdef CONFIG_RELOC
>  extern char _text, _etext;
>  
> -static bool base_address(const void *rebased_addr, unsigned long *addr)
> +bool __attribute__((weak)) arch_base_address(const void *rebased_addr, unsigned long *addr)
>  {
>  	unsigned long ra = (unsigned long)rebased_addr;
>  	unsigned long start = (unsigned long)&_text;
> @@ -27,7 +27,7 @@ static bool base_address(const void *rebased_addr, unsigned long *addr)
>  	return true;
>  }
>  #else
> -static bool base_address(const void *rebased_addr, unsigned long *addr)
> +bool __attribute__((weak)) arch_base_address(const void *rebased_addr, unsigned long *addr)
>  {
>  	*addr = (unsigned long)rebased_addr;
>  	return true;
> @@ -45,13 +45,13 @@ static void print_stack(const void **return_addrs, int depth,
>  	/* @addr indicates a non-return address, as expected by the stack
>  	 * pretty printer script. */
>  	if (depth > 0 && !top_is_return_address) {
> -		if (base_address(return_addrs[0], &addr))
> +		if (arch_base_address(return_addrs[0], &addr))
>  			printf(" @%lx", addr);
>  		i++;
>  	}
>  
>  	for (; i < depth; i++) {
> -		if (base_address(return_addrs[i], &addr))
> +		if (arch_base_address(return_addrs[i], &addr))
>  			printf(" %lx", addr);
>  	}
>  	printf("\n");
> diff --git a/lib/stack.h b/lib/stack.h
> index 6edc84344b51..df076d94bf8f 100644
> --- a/lib/stack.h
> +++ b/lib/stack.h
> @@ -34,4 +34,6 @@ static inline int backtrace_frame(const void *frame, const void **return_addrs,
>  }
>  #endif
>  
> +bool __attribute__((weak)) arch_base_address(const void *rebased_addr, unsigned long *addr);
> +
>  #endif