From 3ba150fb21207e4a7f4b600eb2dbbe83f94571fe Mon Sep 17 00:00:00 2001 From: Ganesh Goudar Date: Mon, 30 Nov 2020 14:00:57 +0530 Subject: [PATCH] lkdtm/powerpc: Add SLB multihit test To check machine check handling, add support to inject slb multihit errors. Co-developed-by: Mahesh Salgaonkar Signed-off-by: Mahesh Salgaonkar Signed-off-by: Ganesh Goudar [mpe: Use CONFIG_PPC_BOOK3S_64 to fix compile errors reported by lkp@intel.com] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20201130083057.135610-1-ganeshgr@linux.ibm.com --- arch/powerpc/include/asm/book3s/64/mmu-hash.h | 28 +++++- arch/powerpc/mm/book3s64/hash_utils.c | 1 + arch/powerpc/mm/book3s64/slb.c | 27 ------ drivers/misc/lkdtm/Makefile | 1 + drivers/misc/lkdtm/core.c | 3 + drivers/misc/lkdtm/lkdtm.h | 3 + drivers/misc/lkdtm/powerpc.c | 120 ++++++++++++++++++++++++++ tools/testing/selftests/lkdtm/tests.txt | 1 + 8 files changed, 156 insertions(+), 28 deletions(-) create mode 100644 drivers/misc/lkdtm/powerpc.c diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h index 9192cb0..066b1d34 100644 --- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h +++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h @@ -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_ */ diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index e0fe1a4..73b06ad 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -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 diff --git a/arch/powerpc/mm/book3s64/slb.c b/arch/powerpc/mm/book3s64/slb.c index 6d720c1..5845679 100644 --- a/arch/powerpc/mm/book3s64/slb.c +++ b/arch/powerpc/mm/book3s64/slb.c @@ -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) diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile index c70b382..5a92c74 100644 --- a/drivers/misc/lkdtm/Makefile +++ b/drivers/misc/lkdtm/Makefile @@ -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 diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c index 97803f2..1f612c7 100644 --- a/drivers/misc/lkdtm/core.c +++ b/drivers/misc/lkdtm/core.c @@ -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 }; diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index 6dec4c9..79ec05c 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -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 diff --git a/drivers/misc/lkdtm/powerpc.c b/drivers/misc/lkdtm/powerpc.c new file mode 100644 index 0000000..077c9f9 --- /dev/null +++ b/drivers/misc/lkdtm/powerpc.c @@ -0,0 +1,120 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "lkdtm.h" +#include +#include +#include + +/* 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"); + } +} diff --git a/tools/testing/selftests/lkdtm/tests.txt b/tools/testing/selftests/lkdtm/tests.txt index 74a8d32..18e4599 100644 --- a/tools/testing/selftests/lkdtm/tests.txt +++ b/tools/testing/selftests/lkdtm/tests.txt @@ -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 -- 2.7.4