[PATCH RESEND 1/2] riscv/purgatory: return bool from verify_sha256_digest

[PATCH RESEND 1/2] riscv/purgatory: return bool from verify_sha256_digest

[Thorsten Blum]

Change the function's return type from int to bool and return the result
of memcmp() directly to simplify the code.  While at it, cast ->start to
'const u8 *' to better match the expected type.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
 arch/riscv/purgatory/purgatory.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/purgatory/purgatory.c b/arch/riscv/purgatory/purgatory.c
index bbd5cfa4d741..15c72dafa3d8 100644
--- a/arch/riscv/purgatory/purgatory.c
+++ b/arch/riscv/purgatory/purgatory.c
@@ -17,7 +17,7 @@ u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory");
 
 struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory");
 
-static int verify_sha256_digest(void)
+static bool verify_sha256_digest(void)
 {
 	struct kexec_sha_region *ptr, *end;
 	struct sha256_ctx sctx;
@@ -26,11 +26,10 @@ static int verify_sha256_digest(void)
 	sha256_init(&sctx);
 	end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);
 	for (ptr = purgatory_sha_regions; ptr < end; ptr++)
-		sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
+		sha256_update(&sctx, (const u8 *)(ptr->start), ptr->len);
 	sha256_final(&sctx, digest);
-	if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)) != 0)
-		return 1;
-	return 0;
+
+	return memcmp(digest, purgatory_sha256_digest, sizeof(digest));
 }
 
 /* workaround for a warning with -Wmissing-prototypes */

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[PATCH RESEND 2/2] riscv/purgatory: add asm/purgatory.h

[Thorsten Blum]

Add arch/riscv/include/asm/purgatory.h and provide the purgatory()
prototype via the architecture header, mirroring the x86 layout.

Remove the workaround from arch/riscv/purgatory/purgatory.c.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
 arch/riscv/include/asm/purgatory.h | 11 +++++++++++
 arch/riscv/purgatory/purgatory.c   |  5 +----
 2 files changed, 12 insertions(+), 4 deletions(-)
 create mode 100644 arch/riscv/include/asm/purgatory.h

diff --git a/arch/riscv/include/asm/purgatory.h b/arch/riscv/include/asm/purgatory.h
new file mode 100644
index 000000000000..a63687be2517
--- /dev/null
+++ b/arch/riscv/include/asm/purgatory.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_RISCV_PURGATORY_H
+#define _ASM_RISCV_PURGATORY_H
+
+#ifndef __ASSEMBLER__
+#include <linux/purgatory.h>
+
+extern void purgatory(void);
+#endif	/* __ASSEMBLER__ */
+
+#endif /* _ASM_RISCV_PURGATORY_H */
diff --git a/arch/riscv/purgatory/purgatory.c b/arch/riscv/purgatory/purgatory.c
index 15c72dafa3d8..6a6e6f611a56 100644
--- a/arch/riscv/purgatory/purgatory.c
+++ b/arch/riscv/purgatory/purgatory.c
@@ -8,9 +8,9 @@
  *
  */
 
-#include <linux/purgatory.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
+#include <asm/purgatory.h>
 #include <asm/string.h>
 
 u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory");
@@ -32,9 +32,6 @@ static bool verify_sha256_digest(void)
 	return memcmp(digest, purgatory_sha256_digest, sizeof(digest));
 }
 
-/* workaround for a warning with -Wmissing-prototypes */
-void purgatory(void);
-
 void purgatory(void)
 {
 	if (verify_sha256_digest())

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Re: [PATCH RESEND 1/2] riscv/purgatory: return bool from verify_sha256_digest

[Eric Biggers]

On Fri, May 08, 2026 at 04:35:44PM +0200, Thorsten Blum wrote:
> Change the function's return type from int to bool and return the result
> of memcmp() directly to simplify the code.  While at it, cast ->start to
> 'const u8 *' to better match the expected type.
> 
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
>  arch/riscv/purgatory/purgatory.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/riscv/purgatory/purgatory.c b/arch/riscv/purgatory/purgatory.c
> index bbd5cfa4d741..15c72dafa3d8 100644
> --- a/arch/riscv/purgatory/purgatory.c
> +++ b/arch/riscv/purgatory/purgatory.c
> @@ -17,7 +17,7 @@ u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory");
>  
>  struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory");
>  
> -static int verify_sha256_digest(void)
> +static bool verify_sha256_digest(void)
>  {
>  	struct kexec_sha_region *ptr, *end;
>  	struct sha256_ctx sctx;
> @@ -26,11 +26,10 @@ static int verify_sha256_digest(void)
>  	sha256_init(&sctx);
>  	end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);
>  	for (ptr = purgatory_sha_regions; ptr < end; ptr++)
> -		sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
> +		sha256_update(&sctx, (const u8 *)(ptr->start), ptr->len);
>  	sha256_final(&sctx, digest);
> -	if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)) != 0)
> -		return 1;
> -	return 0;
> +
> +	return memcmp(digest, purgatory_sha256_digest, sizeof(digest));
>  }

So true on failure and false on success?  Might make sense to flip that.

- Eric

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Re: [PATCH RESEND 1/2] riscv/purgatory: return bool from verify_sha256_digest

[Thorsten Blum]

On Fri, May 08, 2026 at 06:41:37PM +0000, Eric Biggers wrote:
> On Fri, May 08, 2026 at 04:35:44PM +0200, Thorsten Blum wrote:
> > Change the function's return type from int to bool and return the result
> > of memcmp() directly to simplify the code.  While at it, cast ->start to
> > 'const u8 *' to better match the expected type.
> > 
> > Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> > ---
> >  arch/riscv/purgatory/purgatory.c | 9 ++++-----
> >  1 file changed, 4 insertions(+), 5 deletions(-)
> > 
> > diff --git a/arch/riscv/purgatory/purgatory.c b/arch/riscv/purgatory/purgatory.c
> > index bbd5cfa4d741..15c72dafa3d8 100644
> > --- a/arch/riscv/purgatory/purgatory.c
> > +++ b/arch/riscv/purgatory/purgatory.c
> > @@ -17,7 +17,7 @@ u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory");
> >  
> >  struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory");
> >  
> > -static int verify_sha256_digest(void)
> > +static bool verify_sha256_digest(void)
> >  {
> >  	struct kexec_sha_region *ptr, *end;
> >  	struct sha256_ctx sctx;
> > @@ -26,11 +26,10 @@ static int verify_sha256_digest(void)
> >  	sha256_init(&sctx);
> >  	end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);
> >  	for (ptr = purgatory_sha_regions; ptr < end; ptr++)
> > -		sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
> > +		sha256_update(&sctx, (const u8 *)(ptr->start), ptr->len);
> >  	sha256_final(&sctx, digest);
> > -	if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)) != 0)
> > -		return 1;
> > -	return 0;
> > +
> > +	return memcmp(digest, purgatory_sha256_digest, sizeof(digest));
> >  }
> 
> So true on failure and false on success?  Might make sense to flip that.

Ahem yes, that should obviously be flipped. I'll send a v2. Thanks!

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