Commit 030f7951 authored Jul 16, 2024 by Heiko Carstens Committed by Vasily Gorbik Jul 23, 2024

s390/uaccess: Make s390_kernel_write() usable for decompressor



To avoid lots of ifdefs in C code make s390_kernel_write() usable for
the decompressor: simply use memcpy() for this case since there is no
write protection enabled that early.

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Tested-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

parent ace76fac

arch/s390/include/asm/uaccess.h

+8 −1

Original line number	Diff line number	Diff line
		@@ -332,7 +332,14 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo
		return __clear_user(to, n);
		}

		void s390_kernel_write(void dst, const void *src, size_t size);
		void __s390_kernel_write(void dst, const void *src, size_t size);

		static inline void s390_kernel_write(void dst, const void *src, size_t size)
		{
		if (__is_defined(__DECOMPRESSOR))
		return memcpy(dst, src, size);
		return __s390_kernel_write(dst, src, size);
		}

		int __noreturn __put_kernel_bad(void);

arch/s390/mm/maccess.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -48,7 +48,7 @@ static notrace long s390_kernel_write_odd(void dst, const void src, size_t siz
		}

		/*
		* s390_kernel_write - write to kernel memory bypassing DAT
		* __s390_kernel_write - write to kernel memory bypassing DAT
		* @dst: destination address
		* @src: source address
		* @size: number of bytes to copy
		@@ -61,7 +61,7 @@ static notrace long s390_kernel_write_odd(void dst, const void src, size_t siz
		*/
		static DEFINE_SPINLOCK(s390_kernel_write_lock);

		notrace void s390_kernel_write(void dst, const void *src, size_t size)
		notrace void __s390_kernel_write(void dst, const void *src, size_t size)
		{
		void *tmp = dst;
		unsigned long flags;