[PATCH v5] lkdtm/powerpc: Add SLB multihit test
Ganesh Goudar
ganeshgr at linux.ibm.com
Mon Nov 30 19:30:57 AEDT 2020
To check machine check handling, add support to inject slb
multihit errors.
Cc: Kees Cook <keescook at chromium.org>
Cc: Michal Suchánek <msuchanek at suse.de>
Co-developed-by: Mahesh Salgaonkar <mahesh at linux.ibm.com>
Signed-off-by: Mahesh Salgaonkar <mahesh at linux.ibm.com>
Signed-off-by: Ganesh Goudar <ganeshgr at linux.ibm.com>
---
v5:
- Insert entries at SLB_NUM_BOLTED and SLB_NUM_BOLTED +1, remove index
allocating helper function.
- Move mk_esid_data and mk_vsid_data helpers to asm/book3s/64/mmu-hash.h.
- Use mmu_linear_psize and mmu_vmalloc_psize to get page size.
- Use !radix_enabled() to check if we are in HASH mode.
- And other minor improvements.
v1-v4:
- No major changes here for this patch, This patch was initially posted
along with the other patch which got accepted.
https://git.kernel.org/powerpc/c/8d0e2101274358d9b6b1f27232b40253ca48bab5
---
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 683a9c7d1b03..8b9f07900395 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -842,6 +842,32 @@ 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 24702c0a92e0..38076a998850 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 c30fcbfa0e32..985706acb0e5 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 c70b3822013f..f37ecfb0a707 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_PPC64) += 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 97803f213d9d..538098dc5aec 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_PPC64
+ CRASHTYPE(PPC_SLB_MULTIHIT),
+#endif
};
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
index 6dec4c9b442f..79ec05c18dd1 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 000000000000..077c9f9ed8d0
--- /dev/null
+++ b/drivers/misc/lkdtm/powerpc.c
@@ -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");
+ }
+}
diff --git a/tools/testing/selftests/lkdtm/tests.txt b/tools/testing/selftests/lkdtm/tests.txt
index 74a8d329a72c..18e4599863c0 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
--
2.26.2
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