[PATCH v14 14/22] selftests/vm: Introduce generic abstractions
Ram Pai
linuxram at us.ibm.com
Tue Jul 17 23:49:17 AEST 2018
Introduce generic abstractions and provide architecture
specific implementation for the abstractions.
cc: Dave Hansen <dave.hansen at intel.com>
cc: Florian Weimer <fweimer at redhat.com>
Signed-off-by: Ram Pai <linuxram at us.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman at linux.ibm.com>
---
tools/testing/selftests/vm/pkey-helpers.h | 16 ++++-
tools/testing/selftests/vm/pkey-powerpc.h | 93 ++++++++++++++++++++++++++
tools/testing/selftests/vm/pkey-x86.h | 15 ++++
tools/testing/selftests/vm/protection_keys.c | 52 ++++++++------
4 files changed, 153 insertions(+), 23 deletions(-)
create mode 100644 tools/testing/selftests/vm/pkey-powerpc.h
diff --git a/tools/testing/selftests/vm/pkey-helpers.h b/tools/testing/selftests/vm/pkey-helpers.h
index 52a1152..321bbbd 100644
--- a/tools/testing/selftests/vm/pkey-helpers.h
+++ b/tools/testing/selftests/vm/pkey-helpers.h
@@ -74,8 +74,13 @@ static inline void sigsafe_printf(const char *format, ...)
} \
} while (0)
+__attribute__((noinline)) int read_ptr(int *ptr);
+void expected_pkey_fault(int pkey);
+
#if defined(__i386__) || defined(__x86_64__) /* arch */
#include "pkey-x86.h"
+#elif defined(__powerpc64__) /* arch */
+#include "pkey-powerpc.h"
#else /* arch */
#error Architecture not supported
#endif /* arch */
@@ -186,7 +191,16 @@ static inline int open_hugepage_file(int flag)
static inline int get_start_key(void)
{
- return 1;
+ return 0;
+}
+
+static inline u32 *siginfo_get_pkey_ptr(siginfo_t *si)
+{
+#ifdef si_pkey
+ return &si->si_pkey;
+#else
+ return (u32 *)(((u8 *)si) + si_pkey_offset);
+#endif
}
#endif /* _PKEYS_HELPER_H */
diff --git a/tools/testing/selftests/vm/pkey-powerpc.h b/tools/testing/selftests/vm/pkey-powerpc.h
new file mode 100644
index 0000000..b0d1abe
--- /dev/null
+++ b/tools/testing/selftests/vm/pkey-powerpc.h
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _PKEYS_POWERPC_H
+#define _PKEYS_POWERPC_H
+
+#ifndef SYS_mprotect_key
+# define SYS_mprotect_key 386
+#endif
+#ifndef SYS_pkey_alloc
+# define SYS_pkey_alloc 384
+# define SYS_pkey_free 385
+#endif
+#define REG_IP_IDX PT_NIP
+#define REG_TRAPNO PT_TRAP
+#define gregs gp_regs
+#define fpregs fp_regs
+#define si_pkey_offset 0x20
+
+#ifndef PKEY_DISABLE_ACCESS
+# define PKEY_DISABLE_ACCESS 0x3 /* disable read and write */
+#endif
+
+#ifndef PKEY_DISABLE_WRITE
+# define PKEY_DISABLE_WRITE 0x2
+#endif
+
+#define NR_PKEYS 32
+#define NR_RESERVED_PKEYS_4K 27 /* pkey-0, pkey-1, exec-only-pkey
+ and 24 other keys that cannot be
+ represented in the PTE */
+#define NR_RESERVED_PKEYS_64K 3 /* pkey-0, pkey-1 and exec-only-pkey */
+#define PKEY_BITS_PER_PKEY 2
+#define HPAGE_SIZE (1UL << 24)
+#define PAGE_SIZE (1UL << 16)
+#define pkey_reg_t u64
+#define PKEY_REG_FMT "%016lx"
+#define HUGEPAGE_FILE "/sys/kernel/mm/hugepages/hugepages-16384kB/nr_hugepages"
+
+static inline u32 pkey_bit_position(int pkey)
+{
+ return (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
+}
+
+static inline pkey_reg_t __read_pkey_reg(void)
+{
+ pkey_reg_t pkey_reg;
+
+ asm volatile("mfspr %0, 0xd" : "=r" (pkey_reg));
+
+ return pkey_reg;
+}
+
+static inline void __write_pkey_reg(pkey_reg_t pkey_reg)
+{
+ pkey_reg_t eax = pkey_reg;
+
+ dprintf4("%s() changing "PKEY_REG_FMT" to "PKEY_REG_FMT"\n",
+ __func__, __read_pkey_reg(), pkey_reg);
+
+ asm volatile("mtspr 0xd, %0" : : "r" ((unsigned long)(eax)) : "memory");
+
+ dprintf4("%s() pkey register after changing "PKEY_REG_FMT" to "
+ PKEY_REG_FMT"\n", __func__, __read_pkey_reg(),
+ pkey_reg);
+}
+
+static inline int cpu_has_pku(void)
+{
+ return 1;
+}
+
+static inline int arch_reserved_keys(void)
+{
+ if (sysconf(_SC_PAGESIZE) == 4096)
+ return NR_RESERVED_PKEYS_4K;
+ else
+ return NR_RESERVED_PKEYS_64K;
+}
+
+void expect_fault_on_read_execonly_key(void *p1, int pkey)
+{
+ /* powerpc does not allow userspace to change permissions of exec-only
+ * keys since those keys are not allocated by userspace. The signal
+ * handler wont be able to reset the permissions, which means the code
+ * will infinitely continue to segfault here.
+ */
+ return;
+}
+
+/* 8-bytes of instruction * 16384bytes = 1 page */
+#define __page_o_noops() asm(".rept 16384 ; nop; .endr")
+
+#endif /* _PKEYS_POWERPC_H */
diff --git a/tools/testing/selftests/vm/pkey-x86.h b/tools/testing/selftests/vm/pkey-x86.h
index d5fa299..f5d0ff2 100644
--- a/tools/testing/selftests/vm/pkey-x86.h
+++ b/tools/testing/selftests/vm/pkey-x86.h
@@ -42,6 +42,7 @@
#endif
#define NR_PKEYS 16
+#define NR_RESERVED_PKEYS 2 /* pkey-0 and exec-only-pkey */
#define PKEY_BITS_PER_PKEY 2
#define HPAGE_SIZE (1UL<<21)
#define PAGE_SIZE 4096
@@ -161,4 +162,18 @@ int pkey_reg_xstate_offset(void)
return xstate_offset;
}
+static inline int arch_reserved_keys(void)
+{
+ return NR_RESERVED_PKEYS;
+}
+
+void expect_fault_on_read_execonly_key(void *p1, int pkey)
+{
+ int ptr_contents;
+
+ ptr_contents = read_ptr(p1);
+ dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
+ expected_pkey_fault(pkey);
+}
+
#endif /* _PKEYS_X86_H */
diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index 304f74f..18e1bb7 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -197,17 +197,18 @@ void dump_mem(void *dumpme, int len_bytes)
int pkey_faults;
int last_si_pkey = -1;
+void pkey_access_allow(int pkey);
void signal_handler(int signum, siginfo_t *si, void *vucontext)
{
ucontext_t *uctxt = vucontext;
int trapno;
unsigned long ip;
char *fpregs;
+#if defined(__i386__) || defined(__x86_64__) /* arch */
pkey_reg_t *pkey_reg_ptr;
- u64 siginfo_pkey;
+#endif /* defined(__i386__) || defined(__x86_64__) */
+ u32 siginfo_pkey;
u32 *si_pkey_ptr;
- int pkey_reg_offset;
- fpregset_t fpregset;
dprint_in_signal = 1;
dprintf1(">>>>===============SIGSEGV============================\n");
@@ -217,12 +218,14 @@ void signal_handler(int signum, siginfo_t *si, void *vucontext)
trapno = uctxt->uc_mcontext.gregs[REG_TRAPNO];
ip = uctxt->uc_mcontext.gregs[REG_IP_IDX];
- fpregset = uctxt->uc_mcontext.fpregs;
- fpregs = (void *)fpregset;
+ fpregs = (char *) uctxt->uc_mcontext.fpregs;
dprintf2("%s() trapno: %d ip: 0x%016lx info->si_code: %s/%d\n",
__func__, trapno, ip, si_code_str(si->si_code),
si->si_code);
+
+#if defined(__i386__) || defined(__x86_64__) /* arch */
+
#ifdef __i386__
/*
* 32-bit has some extra padding so that userspace can tell whether
@@ -230,20 +233,21 @@ void signal_handler(int signum, siginfo_t *si, void *vucontext)
* state. We just assume that it is here.
*/
fpregs += 0x70;
-#endif
- pkey_reg_offset = pkey_reg_xstate_offset();
- pkey_reg_ptr = (void *)(&fpregs[pkey_reg_offset]);
+#endif /* __i386__ */
- dprintf1("siginfo: %p\n", si);
- dprintf1(" fpregs: %p\n", fpregs);
+ pkey_reg_ptr = (void *)(&fpregs[pkey_reg_xstate_offset()]);
/*
- * If we got a PKEY fault, we *HAVE* to have at least one bit set in
+ * If we got a key fault, we *HAVE* to have at least one bit set in
* here.
*/
dprintf1("pkey_reg_xstate_offset: %d\n", pkey_reg_xstate_offset());
if (DEBUG_LEVEL > 4)
dump_mem(pkey_reg_ptr - 128, 256);
pkey_assert(*pkey_reg_ptr);
+#endif /* defined(__i386__) || defined(__x86_64__) */
+
+ dprintf1("siginfo: %p\n", si);
+ dprintf1(" fpregs: %p\n", fpregs);
if ((si->si_code == SEGV_MAPERR) ||
(si->si_code == SEGV_ACCERR) ||
@@ -252,22 +256,28 @@ void signal_handler(int signum, siginfo_t *si, void *vucontext)
exit(4);
}
- si_pkey_ptr = (u32 *)(((u8 *)si) + si_pkey_offset);
+ si_pkey_ptr = siginfo_get_pkey_ptr(si);
dprintf1("si_pkey_ptr: %p\n", si_pkey_ptr);
- dump_mem((u8 *)si_pkey_ptr - 8, 24);
+ dump_mem(si_pkey_ptr - 8, 24);
siginfo_pkey = *si_pkey_ptr;
pkey_assert(siginfo_pkey < NR_PKEYS);
last_si_pkey = siginfo_pkey;
- dprintf1("signal pkey_reg from xsave: "PKEY_REG_FMT"\n", *pkey_reg_ptr);
/*
* need __read_pkey_reg() version so we do not do shadow_pkey_reg
* checking
*/
dprintf1("signal pkey_reg from pkey_reg: "PKEY_REG_FMT"\n",
__read_pkey_reg());
- dprintf1("pkey from siginfo: %jx\n", siginfo_pkey);
- *(u64 *)pkey_reg_ptr = 0x00000000;
+#if defined(__i386__) || defined(__x86_64__) /* arch */
+ dprintf1("signal pkey_reg from xsave: "PKEY_REG_FMT"\n", *pkey_reg_ptr);
+ *(u64 *)pkey_reg_ptr &= clear_pkey_flags(siginfo_pkey,
+ PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE);
+#elif __powerpc64__
+ pkey_access_allow(siginfo_pkey);
+#endif
+ shadow_pkey_reg &= clear_pkey_flags(siginfo_pkey,
+ PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE);
dprintf1("WARNING: set PKEY_REG=0 to allow faulting instruction "
"to continue\n");
pkey_faults++;
@@ -1328,9 +1338,8 @@ void test_executing_on_unreadable_memory(int *ptr, u16 pkey)
madvise(p1, PAGE_SIZE, MADV_DONTNEED);
lots_o_noops_around_write(&scratch);
do_not_expect_pkey_fault("executing on PROT_EXEC memory");
- ptr_contents = read_ptr(p1);
- dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
- expected_pkey_fault(pkey);
+
+ expect_fault_on_read_execonly_key(p1, pkey);
}
void test_implicit_mprotect_exec_only_memory(int *ptr, u16 pkey)
@@ -1357,9 +1366,8 @@ void test_implicit_mprotect_exec_only_memory(int *ptr, u16 pkey)
madvise(p1, PAGE_SIZE, MADV_DONTNEED);
lots_o_noops_around_write(&scratch);
do_not_expect_pkey_fault("executing on PROT_EXEC memory");
- ptr_contents = read_ptr(p1);
- dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
- expected_pkey_fault(UNKNOWN_PKEY);
+
+ expect_fault_on_read_execonly_key(p1, UNKNOWN_PKEY);
/*
* Put the memory back to non-PROT_EXEC. Should clear the
--
1.7.1
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