[PATCH] random: vDSO: move prototype of arch chacha function to vdso/getrandom.h

["Jason A. Donenfeld" <Jason@zx2c4.com>]

Having the prototype for __arch_chacha20_blocks_nostack in
arch/x86/include/asm/vdso/getrandom.h meant that the prototype and large
doc comment were cloned by every architecture, which has been causing
unnecessary churn. Instead move it into include/vdso/getrandom.h, where
it can be shared by all archs implementing it.

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 arch/x86/include/asm/vdso/getrandom.h | 13 -------------
 include/vdso/getrandom.h              | 13 +++++++++++++
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/vdso/getrandom.h b/arch/x86/include/asm/vdso/getrandom.h
index b96e674cafde..ff5334ad32a0 100644
--- a/arch/x86/include/asm/vdso/getrandom.h
+++ b/arch/x86/include/asm/vdso/getrandom.h
@@ -37,19 +37,6 @@ static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void
 	return &__vdso_rng_data;
 }
 
-/**
- * __arch_chacha20_blocks_nostack - Generate ChaCha20 stream without using the stack.
- * @dst_bytes:	Destination buffer to hold @nblocks * 64 bytes of output.
- * @key:	32-byte input key.
- * @counter:	8-byte counter, read on input and updated on return.
- * @nblocks:	Number of blocks to generate.
- *
- * Generates a given positive number of blocks of ChaCha20 output with nonce=0, and does not write
- * to any stack or memory outside of the parameters passed to it, in order to mitigate stack data
- * leaking into forked child processes.
- */
-extern void __arch_chacha20_blocks_nostack(u8 *dst_bytes, const u32 *key, u32 *counter, size_t nblocks);
-
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ASM_VDSO_GETRANDOM_H */
diff --git a/include/vdso/getrandom.h b/include/vdso/getrandom.h
index a8b7c14b0ae0..4cf02e678f5e 100644
--- a/include/vdso/getrandom.h
+++ b/include/vdso/getrandom.h
@@ -43,4 +43,17 @@ struct vgetrandom_state {
 	bool 			in_use;
 };
 
+/**
+ * __arch_chacha20_blocks_nostack - Generate ChaCha20 stream without using the stack.
+ * @dst_bytes:	Destination buffer to hold @nblocks * 64 bytes of output.
+ * @key:	32-byte input key.
+ * @counter:	8-byte counter, read on input and updated on return.
+ * @nblocks:	Number of blocks to generate.
+ *
+ * Generates a given positive number of blocks of ChaCha20 output with nonce=0, and does not write
+ * to any stack or memory outside of the parameters passed to it, in order to mitigate stack data
+ * leaking into forked child processes.
+ */
+extern void __arch_chacha20_blocks_nostack(u8 *dst_bytes, const u32 *key, u32 *counter, size_t nblocks);
+
 #endif /* _VDSO_GETRANDOM_H */
-- 
2.46.0