[PATCH v2 27/33] s390/mm: Define KMSAN metadata for vmalloc and modules
From: Ilya Leoshkevich <iii@linux.ibm.com>
Date: 2023-11-21 22:17:01
Also in:
linux-mm, linux-s390, lkml
Subsystem:
s390 architecture, s390 mm, the rest · Maintainers:
Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Gerald Schaefer, Linus Torvalds
The pages for the KMSAN metadata associated with most kernel mappings are taken from memblock by the common code. However, vmalloc and module metadata needs to be defined by the architectures. Be a little bit more careful than x86: allocate exactly MODULES_LEN for the module shadow and origins, and then take 2/3 of vmalloc for the vmalloc shadow and origins. This ensures that users passing small vmalloc= values on the command line do not cause module metadata collisions. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> --- arch/s390/boot/startup.c | 8 ++++++++ arch/s390/include/asm/pgtable.h | 10 ++++++++++ 2 files changed, 18 insertions(+)
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index 8104e0e3d188..e37e7ffda430 100644
--- a/arch/s390/boot/startup.c
+++ b/arch/s390/boot/startup.c@@ -253,9 +253,17 @@ static unsigned long setup_kernel_memory_layout(void) MODULES_END = round_down(__abs_lowcore, _SEGMENT_SIZE); MODULES_VADDR = MODULES_END - MODULES_LEN; VMALLOC_END = MODULES_VADDR; +#ifdef CONFIG_KMSAN + VMALLOC_END -= MODULES_LEN * 2; +#endif /* allow vmalloc area to occupy up to about 1/2 of the rest virtual space left */ vmalloc_size = min(vmalloc_size, round_down(VMALLOC_END / 2, _REGION3_SIZE)); +#ifdef CONFIG_KMSAN + /* take 2/3 of vmalloc area for KMSAN shadow and origins */ + vmalloc_size = round_down(vmalloc_size / 3, _REGION3_SIZE); + VMALLOC_END -= vmalloc_size * 2; +#endif VMALLOC_START = VMALLOC_END - vmalloc_size; /* split remaining virtual space between 1:1 mapping & vmemmap array */
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 601e87fa8a9a..d764abeb9e6d 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h@@ -107,6 +107,16 @@ static inline int is_module_addr(void *addr) return 1; } +#ifdef CONFIG_KMSAN +#define KMSAN_VMALLOC_SIZE (VMALLOC_END - VMALLOC_START) +#define KMSAN_VMALLOC_SHADOW_START VMALLOC_END +#define KMSAN_VMALLOC_ORIGIN_START (KMSAN_VMALLOC_SHADOW_START + \ + KMSAN_VMALLOC_SIZE) +#define KMSAN_MODULES_SHADOW_START (KMSAN_VMALLOC_ORIGIN_START + \ + KMSAN_VMALLOC_SIZE) +#define KMSAN_MODULES_ORIGIN_START (KMSAN_MODULES_SHADOW_START + MODULES_LEN) +#endif + /* * A 64 bit pagetable entry of S390 has following format: * | PFRA |0IPC| OS |
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2.41.0