lkdtm/powerpc: Add SLB multihit test

To check machine check handling, add support to inject slb
multihit errors.

Co-developed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
[mpe: Use CONFIG_PPC_BOOK3S_64 to fix compile errors reported by lkp@intel.com]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201130083057.135610-1-ganeshgr@linux.ibm.com
This commit is contained in:
Ganesh Goudar 2020-11-30 14:00:57 +05:30 committed by Michael Ellerman
parent 6c58b1b41b
commit 3ba150fb21
8 changed files with 156 additions and 28 deletions

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@ -843,6 +843,32 @@ static inline unsigned long get_kernel_vsid(unsigned long ea, int ssize)
unsigned htab_shift_for_mem_size(unsigned long mem_size);
#endif /* __ASSEMBLY__ */
enum slb_index {
LINEAR_INDEX = 0, /* Kernel linear map (0xc000000000000000) */
KSTACK_INDEX = 1, /* Kernel stack map */
};
#define slb_esid_mask(ssize) \
(((ssize) == MMU_SEGSIZE_256M) ? ESID_MASK : ESID_MASK_1T)
static inline unsigned long mk_esid_data(unsigned long ea, int ssize,
enum slb_index index)
{
return (ea & slb_esid_mask(ssize)) | SLB_ESID_V | index;
}
static inline unsigned long __mk_vsid_data(unsigned long vsid, int ssize,
unsigned long flags)
{
return (vsid << slb_vsid_shift(ssize)) | flags |
((unsigned long)ssize << SLB_VSID_SSIZE_SHIFT);
}
static inline unsigned long mk_vsid_data(unsigned long ea, int ssize,
unsigned long flags)
{
return __mk_vsid_data(get_kernel_vsid(ea, ssize), ssize, flags);
}
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_BOOK3S_64_MMU_HASH_H_ */

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@ -112,6 +112,7 @@ int mmu_linear_psize = MMU_PAGE_4K;
EXPORT_SYMBOL_GPL(mmu_linear_psize);
int mmu_virtual_psize = MMU_PAGE_4K;
int mmu_vmalloc_psize = MMU_PAGE_4K;
EXPORT_SYMBOL_GPL(mmu_vmalloc_psize);
#ifdef CONFIG_SPARSEMEM_VMEMMAP
int mmu_vmemmap_psize = MMU_PAGE_4K;
#endif

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@ -28,35 +28,8 @@
#include "internal.h"
enum slb_index {
LINEAR_INDEX = 0, /* Kernel linear map (0xc000000000000000) */
KSTACK_INDEX = 1, /* Kernel stack map */
};
static long slb_allocate_user(struct mm_struct *mm, unsigned long ea);
#define slb_esid_mask(ssize) \
(((ssize) == MMU_SEGSIZE_256M)? ESID_MASK: ESID_MASK_1T)
static inline unsigned long mk_esid_data(unsigned long ea, int ssize,
enum slb_index index)
{
return (ea & slb_esid_mask(ssize)) | SLB_ESID_V | index;
}
static inline unsigned long __mk_vsid_data(unsigned long vsid, int ssize,
unsigned long flags)
{
return (vsid << slb_vsid_shift(ssize)) | flags |
((unsigned long) ssize << SLB_VSID_SSIZE_SHIFT);
}
static inline unsigned long mk_vsid_data(unsigned long ea, int ssize,
unsigned long flags)
{
return __mk_vsid_data(get_kernel_vsid(ea, ssize), ssize, flags);
}
bool stress_slb_enabled __initdata;
static int __init parse_stress_slb(char *p)

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@ -10,6 +10,7 @@ lkdtm-$(CONFIG_LKDTM) += rodata_objcopy.o
lkdtm-$(CONFIG_LKDTM) += usercopy.o
lkdtm-$(CONFIG_LKDTM) += stackleak.o
lkdtm-$(CONFIG_LKDTM) += cfi.o
lkdtm-$(CONFIG_PPC_BOOK3S_64) += powerpc.o
KASAN_SANITIZE_stackleak.o := n
KCOV_INSTRUMENT_rodata.o := n

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@ -176,6 +176,9 @@ static const struct crashtype crashtypes[] = {
#ifdef CONFIG_X86_32
CRASHTYPE(DOUBLE_FAULT),
#endif
#ifdef CONFIG_PPC_BOOK3S_64
CRASHTYPE(PPC_SLB_MULTIHIT),
#endif
};

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@ -102,4 +102,7 @@ void lkdtm_STACKLEAK_ERASING(void);
/* cfi.c */
void lkdtm_CFI_FORWARD_PROTO(void);
/* powerpc.c */
void lkdtm_PPC_SLB_MULTIHIT(void);
#endif

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@ -0,0 +1,120 @@
// SPDX-License-Identifier: GPL-2.0
#include "lkdtm.h"
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <asm/mmu.h>
/* Inserts new slb entries */
static void insert_slb_entry(unsigned long p, int ssize, int page_size)
{
unsigned long flags;
flags = SLB_VSID_KERNEL | mmu_psize_defs[page_size].sllp;
preempt_disable();
asm volatile("slbmte %0,%1" :
: "r" (mk_vsid_data(p, ssize, flags)),
"r" (mk_esid_data(p, ssize, SLB_NUM_BOLTED))
: "memory");
asm volatile("slbmte %0,%1" :
: "r" (mk_vsid_data(p, ssize, flags)),
"r" (mk_esid_data(p, ssize, SLB_NUM_BOLTED + 1))
: "memory");
preempt_enable();
}
/* Inject slb multihit on vmalloc-ed address i.e 0xD00... */
static int inject_vmalloc_slb_multihit(void)
{
char *p;
p = vmalloc(PAGE_SIZE);
if (!p)
return -ENOMEM;
insert_slb_entry((unsigned long)p, MMU_SEGSIZE_1T, mmu_vmalloc_psize);
/*
* This triggers exception, If handled correctly we must recover
* from this error.
*/
p[0] = '!';
vfree(p);
return 0;
}
/* Inject slb multihit on kmalloc-ed address i.e 0xC00... */
static int inject_kmalloc_slb_multihit(void)
{
char *p;
p = kmalloc(2048, GFP_KERNEL);
if (!p)
return -ENOMEM;
insert_slb_entry((unsigned long)p, MMU_SEGSIZE_1T, mmu_linear_psize);
/*
* This triggers exception, If handled correctly we must recover
* from this error.
*/
p[0] = '!';
kfree(p);
return 0;
}
/*
* Few initial SLB entries are bolted. Add a test to inject
* multihit in bolted entry 0.
*/
static void insert_dup_slb_entry_0(void)
{
unsigned long test_address = PAGE_OFFSET, *test_ptr;
unsigned long esid, vsid;
unsigned long i = 0;
test_ptr = (unsigned long *)test_address;
preempt_disable();
asm volatile("slbmfee %0,%1" : "=r" (esid) : "r" (i));
asm volatile("slbmfev %0,%1" : "=r" (vsid) : "r" (i));
/* for i !=0 we would need to mask out the old entry number */
asm volatile("slbmte %0,%1" :
: "r" (vsid),
"r" (esid | SLB_NUM_BOLTED)
: "memory");
asm volatile("slbmfee %0,%1" : "=r" (esid) : "r" (i));
asm volatile("slbmfev %0,%1" : "=r" (vsid) : "r" (i));
/* for i !=0 we would need to mask out the old entry number */
asm volatile("slbmte %0,%1" :
: "r" (vsid),
"r" (esid | (SLB_NUM_BOLTED + 1))
: "memory");
pr_info("%s accessing test address 0x%lx: 0x%lx\n",
__func__, test_address, *test_ptr);
preempt_enable();
}
void lkdtm_PPC_SLB_MULTIHIT(void)
{
if (!radix_enabled()) {
pr_info("Injecting SLB multihit errors\n");
/*
* These need not be separate tests, And they do pretty
* much same thing. In any case we must recover from the
* errors introduced by these functions, machine would not
* survive these tests in case of failure to handle.
*/
inject_vmalloc_slb_multihit();
inject_kmalloc_slb_multihit();
insert_dup_slb_entry_0();
pr_info("Recovered from SLB multihit errors\n");
} else {
pr_err("XFAIL: This test is for ppc64 and with hash mode MMU only\n");
}
}

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@ -68,3 +68,4 @@ USERCOPY_STACK_BEYOND
USERCOPY_KERNEL
STACKLEAK_ERASING OK: the rest of the thread stack is properly erased
CFI_FORWARD_PROTO
PPC_SLB_MULTIHIT Recovered