Kernel/linux-next
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git synced 2024-12-29 17:22:07 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

s390/Kconfig: Select VMAP_STACK unconditionally

Browse Source 
There is no point in supporting !VMAP_STACK kernel builds. VMAP_STACK has
proven to work since many years. Also, since KASAN_VMALLOC is supported,
kernels built with !VMAP_STACK are completely untested.

Therefore select VMAP_STACK unconditionally and remove all config options
and code required for !VMAP_STACK builds.

Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2024-12-02 12:56:38 +01:00 committed by Alexander Gordeev
parent e7256acac3
commit 27939d6cde
5 changed files with 4 additions and 62 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
arch/s390/Kconfig
View File

@ -256,6 +256,7 @@ config S390
select USER_STACKTRACE_SUPPORT
select VDSO_GETRANDOM
select VIRT_CPU_ACCOUNTING
select VMAP_STACK
select ZONE_DMA
# Note: keep the above list sorted alphabetically
@ -689,32 +690,6 @@ config MAX_PHYSMEM_BITS
Increasing the number of bits also increases the kernel image size.
By default 46 bits (64TB) are supported.
config CHECK_STACK
def_bool y
depends on !VMAP_STACK
prompt "Detect kernel stack overflow"
help
This option enables the compiler option -mstack-guard and
-mstack-size if they are available. If the compiler supports them
it will emit additional code to each function prolog to trigger
an illegal operation if the kernel stack is about to overflow.
Say N if you are unsure.
config STACK_GUARD
int "Size of the guard area (128-1024)"
range 128 1024
depends on CHECK_STACK
default "256"
help
This allows you to specify the size of the guard area at the lower
end of the kernel stack. If the kernel stack points into the guard
area on function entry an illegal operation is triggered. The size
needs to be a power of 2. Please keep in mind that the size of an
interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
The minimum size for the stack guard should be 256 for 31 bit and
512 for 64 bit.
endmenu
menu "I/O subsystem"

9
arch/s390/Makefile
View File

@ -72,15 +72,6 @@ cflags-$(CONFIG_FRAME_POINTER) += -fno-optimize-sibling-calls
KBUILD_AFLAGS_DECOMPRESSOR += $(aflags-y)
KBUILD_CFLAGS_DECOMPRESSOR += $(cflags-y)
ifneq ($(call cc-option,-mstack-size=8192 -mstack-guard=128),)
CC_FLAGS_CHECK_STACK := -mstack-size=$(STACK_SIZE)
ifeq ($(call cc-option,-mstack-size=8192),)
CC_FLAGS_CHECK_STACK += -mstack-guard=$(CONFIG_STACK_GUARD)
endif
export CC_FLAGS_CHECK_STACK
cflags-$(CONFIG_CHECK_STACK) += $(CC_FLAGS_CHECK_STACK)
endif
ifdef CONFIG_EXPOLINE
ifdef CONFIG_EXPOLINE_EXTERN
CC_FLAGS_EXPOLINE := -mindirect-branch=thunk-extern

20
arch/s390/kernel/entry.S
View File

@ -52,16 +52,7 @@ _LPP_OFFSET = __LC_LPP
ALT_FACILITY(193)
.endm
.macro CHECK_STACK savearea, lowcore
#ifdef CONFIG_CHECK_STACK
tml %r15,THREAD_SIZE - CONFIG_STACK_GUARD
la %r14,\savearea(\lowcore)
jz stack_overflow
#endif
.endm
.macro CHECK_VMAP_STACK savearea, lowcore, oklabel
#ifdef CONFIG_VMAP_STACK
lgr %r14,%r15
nill %r14,0x10000 - THREAD_SIZE
oill %r14,STACK_INIT_OFFSET
@ -77,9 +68,6 @@ _LPP_OFFSET = __LC_LPP
je \oklabel
la %r14,\savearea(\lowcore)
j stack_overflow
#else
j \oklabel
#endif
.endm
/*
@ -326,8 +314,7 @@ SYM_CODE_START(pgm_check_handler)
jnz 2f # -> enabled, can't be a double fault
tm __LC_PGM_ILC+3(%r13),0x80 # check for per exception
jnz .Lpgm_svcper # -> single stepped svc
2: CHECK_STACK __LC_SAVE_AREA,%r13
aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
2: aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
# CHECK_VMAP_STACK branches to stack_overflow or 4f
CHECK_VMAP_STACK __LC_SAVE_AREA,%r13,4f
3: lg %r15,__LC_KERNEL_STACK(%r13)
@ -394,8 +381,7 @@ SYM_CODE_START(\name)
BPENTER __SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
SIEEXIT __SF_SIE_CONTROL(%r15),%r13
#endif
0: CHECK_STACK __LC_SAVE_AREA,%r13
aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
0: aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
j 2f
1: lctlg %c1,%c1,__LC_KERNEL_ASCE(%r13)
lg %r15,__LC_KERNEL_STACK(%r13)
@ -603,7 +589,6 @@ SYM_CODE_END(early_pgm_check_handler)
.section .kprobes.text, "ax"
#if defined(CONFIG_CHECK_STACK) || defined(CONFIG_VMAP_STACK)
/*
* The synchronous or the asynchronous stack overflowed. We are dead.
* No need to properly save the registers, we are going to panic anyway.
@ -621,7 +606,6 @@ SYM_CODE_START(stack_overflow)
lgr %r2,%r11 # pass pointer to pt_regs
jg kernel_stack_overflow
SYM_CODE_END(stack_overflow)
#endif
.section .data, "aw"
.balign 4

8
arch/s390/kernel/setup.c
View File

@ -359,25 +359,17 @@ void *restart_stack;
unsigned long stack_alloc(void)
{
#ifdef CONFIG_VMAP_STACK
void *ret;
ret = __vmalloc_node(THREAD_SIZE, THREAD_SIZE, THREADINFO_GFP,
NUMA_NO_NODE, __builtin_return_address(0));
kmemleak_not_leak(ret);
return (unsigned long)ret;
#else
return __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
#endif
}
void stack_free(unsigned long stack)
{
#ifdef CONFIG_VMAP_STACK
vfree((void *) stack);
#else
free_pages(stack, THREAD_SIZE_ORDER);
#endif
}
static unsigned long __init stack_alloc_early(void)

2
arch/s390/kernel/vdso64/Makefile
View File

@ -5,7 +5,7 @@
include $(srctree)/lib/vdso/Makefile
obj-vdso64 = vdso_user_wrapper.o note.o vgetrandom-chacha.o
obj-cvdso64 = vdso64_generic.o getcpu.o vgetrandom.o
VDSO_CFLAGS_REMOVE := -pg $(CC_FLAGS_FTRACE) $(CC_FLAGS_EXPOLINE) $(CC_FLAGS_CHECK_STACK)
VDSO_CFLAGS_REMOVE := -pg $(CC_FLAGS_FTRACE) $(CC_FLAGS_EXPOLINE)
CFLAGS_REMOVE_getcpu.o = $(VDSO_CFLAGS_REMOVE)
CFLAGS_REMOVE_vgetrandom.o = $(VDSO_CFLAGS_REMOVE)
CFLAGS_REMOVE_vdso64_generic.o = $(VDSO_CFLAGS_REMOVE)