linux.git/arch/s390/boot, branch v6.16

s390/boot: Use strspcy() instead of strcpy()

2025-04-30T09:41:28+00:00

Convert all strcpy() usages to strscpy(). strcpy() is deprecated since
it performs no bounds checking on the destination buffer.

Reviewed-by: Mikhail Zaslonko 
Signed-off-by: Heiko Carstens

watchdog: diag288_wdt: Implement module autoload

2025-04-16T07:26:49+00:00

The s390 specific diag288_wdt watchdog driver makes use of the virtual
watchdog timer, which is available in most machine configurations.
If executing the diagnose instruction with subcode 0x288 results in an
exception the watchdog timer is not available, otherwise it is available.

In order to allow module autoload of the diag288_wdt module, move the
detection of the virtual watchdog timer to early boot code, and provide
its availability as a cpu feature.

This allows to make use of module_cpu_feature_match() to automatically load
the module iff the virtual watchdog timer is available.

Suggested-by: Marc Hartmayer 
Tested-by: Mete Durlu 
Acked-by: Guenter Roeck 
Link: https://lore.kernel.org/r/20250410095036.1525057-1-hca@linux.ibm.com
Signed-off-by: Heiko Carstens

s390/boot: Replace strncpy() with strscpy()

2025-04-14T09:23:22+00:00

Replace the last 2 usages of strncpy() in s390 code with strscpy().

Signed-off-by: Vasily Gorbik 
Reviewed-by: Heiko Carstens 
Signed-off-by: Heiko Carstens

s390/boot: Add sized_strscpy() to enable strscpy() usage

2025-04-14T09:23:22+00:00

Add a simple sized_strscpy() implementation to allow the use of strscpy()
in the decompressor.

Signed-off-by: Vasily Gorbik 
Reviewed-by: Heiko Carstens 
Signed-off-by: Heiko Carstens

s390: Use inline qualifier for all EX_TABLE and ALTERNATIVE inline assemblies

2025-03-18T16:13:51+00:00

Use asm_inline for all inline assemblies which make use of the EX_TABLE or
ALTERNATIVE macros.

These macros expand to many lines and the compiler assumes the number of
lines within an inline assembly is the same as the number of instructions
within an inline assembly. This has an effect on inlining and loop
unrolling decisions.

In order to avoid incorrect assumptions use asm_inline, which tells the
compiler that an inline assembly has the smallest possible size.

In order to avoid confusion when asm_inline should be used or not, since a
couple of inline assemblies are quite large: the rule is to always use
asm_inline whenever the EX_TABLE or ALTERNATIVE macro is used. In specific
cases there may be reasons to not follow this guideline, but that should
be documented with the corresponding code.

Using the inline qualifier everywhere has only a small effect on the kernel
image size:

add/remove: 0/10 grow/shrink: 19/8 up/down: 1492/-1858 (-366)

The only location where this seems to matter is load_unaligned_zeropad()
from word-at-a-time.h where the compiler inlines more functions within the
dcache code, which is indeed code where performance matters.

Suggested-by: Juergen Christ 
Reviewed-by: Juergen Christ 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/boot: Ignore vmlinux.map

2025-03-18T16:13:05+00:00

When building with CONFIG_VMLINUX_MAP=y, a decompressor vmlinux.map file
is generated in the boot directory.

Add this file to .gitignore to ensure Git does not track it.

Signed-off-by: WangYuli 
Link: https://lore.kernel.org/r/F884C733016D6715+20250311030824.675683-1-wangyuli@uniontech.com
Acked-by: Vasily Gorbik 
Signed-off-by: Vasily Gorbik

s390/boot: Convert __diag308() to extable

2025-03-04T16:34:03+00:00

Shorten __diag308() and use regular EX_TABLE program check handling.

Acked-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/boot: Convert detect_diag9c() to extable

2025-03-04T16:34:03+00:00

Shorten detect_diag9c() and use regular EX_TABLE program check handling.

Acked-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/boot: Convert diag500_storage_limit() to extable

2025-03-04T16:34:02+00:00

Shorten diag500_storage_limit() and use regular EX_TABLE program check
handling.

Acked-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/boot: Convert tprot() to extable

2025-03-04T16:34:02+00:00

Shorten tprot() and use regular EX_TABLE program check handling.

Acked-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik