[PATCH v15 13/23] selftests/vm/pkeys: Introduce powerpc support

[Sandipan Das <sandipan@linux.ibm.com>]

From: Ram Pai <linuxram@us.ibm.com>

This makes use of the abstractions added earlier and
introduces support for powerpc.

cc: Dave Hansen <dave.hansen@intel.com>
cc: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
---
 tools/testing/selftests/vm/pkey-helpers.h    |   2 +
 tools/testing/selftests/vm/pkey-powerpc.h    |  93 +++++++
 tools/testing/selftests/vm/protection_keys.c | 269 ++++++++++---------
 3 files changed, 236 insertions(+), 128 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 c929cc09b3cc..5de06d3a81de 100644
--- a/tools/testing/selftests/vm/pkey-helpers.h
+++ b/tools/testing/selftests/vm/pkey-helpers.h
@@ -79,6 +79,8 @@ 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 */
diff --git a/tools/testing/selftests/vm/pkey-powerpc.h b/tools/testing/selftests/vm/pkey-powerpc.h
new file mode 100644
index 000000000000..5ced9c58fa4a
--- /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"
+
+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 get_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/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index dbc2918bec13..1920bca84def 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -168,6 +168,125 @@ void dump_mem(void *dumpme, int len_bytes)
 	}
 }
 
+static u32 hw_pkey_get(int pkey, unsigned long flags)
+{
+	pkey_reg_t pkey_reg = __read_pkey_reg();
+
+	dprintf1("%s(pkey=%d, flags=%lx) = %x / %d\n",
+			__func__, pkey, flags, 0, 0);
+	dprintf2("%s() raw pkey_reg: "PKEY_REG_FMT"\n", __func__, pkey_reg);
+
+	return (u32) get_pkey_bits(pkey_reg, pkey);
+}
+
+static int hw_pkey_set(int pkey, unsigned long rights, unsigned long flags)
+{
+	u32 mask = (PKEY_DISABLE_ACCESS|PKEY_DISABLE_WRITE);
+	pkey_reg_t old_pkey_reg = __read_pkey_reg();
+	pkey_reg_t new_pkey_reg;
+
+	/* make sure that 'rights' only contains the bits we expect: */
+	assert(!(rights & ~mask));
+
+	/* modify bits accordingly in old pkey_reg and assign it */
+	new_pkey_reg = set_pkey_bits(old_pkey_reg, pkey, rights);
+
+	__write_pkey_reg(new_pkey_reg);
+
+	dprintf3("%s(pkey=%d, rights=%lx, flags=%lx) = %x"
+		" pkey_reg now: "PKEY_REG_FMT" old_pkey_reg: "PKEY_REG_FMT"\n",
+		__func__, pkey, rights, flags, 0, __read_pkey_reg(),
+		old_pkey_reg);
+	return 0;
+}
+
+void pkey_disable_set(int pkey, int flags)
+{
+	unsigned long syscall_flags = 0;
+	int ret;
+	int pkey_rights;
+	pkey_reg_t orig_pkey_reg = read_pkey_reg();
+
+	dprintf1("START->%s(%d, 0x%x)\n", __func__,
+		pkey, flags);
+	pkey_assert(flags & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
+
+	pkey_rights = hw_pkey_get(pkey, syscall_flags);
+
+	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
+			pkey, pkey, pkey_rights);
+
+	pkey_assert(pkey_rights >= 0);
+
+	pkey_rights |= flags;
+
+	ret = hw_pkey_set(pkey, pkey_rights, syscall_flags);
+	assert(!ret);
+	/* pkey_reg and flags have the same format */
+	shadow_pkey_reg = set_pkey_bits(shadow_pkey_reg, pkey, pkey_rights);
+	dprintf1("%s(%d) shadow: 0x"PKEY_REG_FMT"\n",
+		__func__, pkey, shadow_pkey_reg);
+
+	pkey_assert(ret >= 0);
+
+	pkey_rights = hw_pkey_get(pkey, syscall_flags);
+	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
+			pkey, pkey, pkey_rights);
+
+	dprintf1("%s(%d) pkey_reg: 0x"PKEY_REG_FMT"\n",
+		__func__, pkey, read_pkey_reg());
+	if (flags)
+		pkey_assert(read_pkey_reg() >= orig_pkey_reg);
+	dprintf1("END<---%s(%d, 0x%x)\n", __func__,
+		pkey, flags);
+}
+
+void pkey_disable_clear(int pkey, int flags)
+{
+	unsigned long syscall_flags = 0;
+	int ret;
+	int pkey_rights = hw_pkey_get(pkey, syscall_flags);
+	pkey_reg_t orig_pkey_reg = read_pkey_reg();
+
+	pkey_assert(flags & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
+
+	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
+			pkey, pkey, pkey_rights);
+	pkey_assert(pkey_rights >= 0);
+
+	pkey_rights &= ~flags;
+
+	ret = hw_pkey_set(pkey, pkey_rights, 0);
+	shadow_pkey_reg = set_pkey_bits(shadow_pkey_reg, pkey, pkey_rights);
+	pkey_assert(ret >= 0);
+
+	pkey_rights = hw_pkey_get(pkey, syscall_flags);
+	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
+			pkey, pkey, pkey_rights);
+
+	dprintf1("%s(%d) pkey_reg: 0x"PKEY_REG_FMT"\n", __func__,
+			pkey, read_pkey_reg());
+	if (flags)
+		assert(read_pkey_reg() <= orig_pkey_reg);
+}
+
+void pkey_write_allow(int pkey)
+{
+	pkey_disable_clear(pkey, PKEY_DISABLE_WRITE);
+}
+void pkey_write_deny(int pkey)
+{
+	pkey_disable_set(pkey, PKEY_DISABLE_WRITE);
+}
+void pkey_access_allow(int pkey)
+{
+	pkey_disable_clear(pkey, PKEY_DISABLE_ACCESS);
+}
+void pkey_access_deny(int pkey)
+{
+	pkey_disable_set(pkey, PKEY_DISABLE_ACCESS);
+}
+
 /* Failed address bound checks: */
 #ifndef SEGV_BNDERR
 # define SEGV_BNDERR		3
@@ -198,11 +317,12 @@ void signal_handler(int signum, siginfo_t *si, void *vucontext)
 	int trapno;
 	unsigned long ip;
 	char *fpregs;
+#if defined(__i386__) || defined(__x86_64__) /* arch */
 	pkey_reg_t *pkey_reg_ptr;
+	int pkey_reg_offset;
+#endif /* arch */
 	u64 siginfo_pkey;
 	u32 *si_pkey_ptr;
-	int pkey_reg_offset;
-	fpregset_t fpregset;
 
 	dprint_in_signal = 1;
 	dprintf1(">>>>===============SIGSEGV============================\n");
@@ -212,12 +332,13 @@ 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
@@ -225,12 +346,10 @@ void signal_handler(int signum, siginfo_t *si, void *vucontext)
 	 * state.  We just assume that it is here.
 	 */
 	fpregs += 0x70;
-#endif
+#endif /* i386 */
 	pkey_reg_offset = pkey_reg_xstate_offset();
 	pkey_reg_ptr = (void *)(&fpregs[pkey_reg_offset]);
 
-	dprintf1("siginfo: %p\n", si);
-	dprintf1(" fpregs: %p\n", fpregs);
 	/*
 	 * If we got a PKEY fault, we *HAVE* to have at least one bit set in
 	 * here.
@@ -239,6 +358,10 @@ void signal_handler(int signum, siginfo_t *si, void *vucontext)
 	if (DEBUG_LEVEL > 4)
 		dump_mem(pkey_reg_ptr - 128, 256);
 	pkey_assert(*pkey_reg_ptr);
+#endif /* arch */
+
+	dprintf1("siginfo: %p\n", si);
+	dprintf1(" fpregs: %p\n", fpregs);
 
 	if ((si->si_code == SEGV_MAPERR) ||
 	    (si->si_code == SEGV_ACCERR) ||
@@ -247,14 +370,13 @@ 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);
 	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
@@ -262,8 +384,14 @@ void signal_handler(int signum, siginfo_t *si, void *vucontext)
 	dprintf1("signal pkey_reg from  pkey_reg: "PKEY_REG_FMT"\n",
 			__read_pkey_reg());
 	dprintf1("pkey from siginfo: %jx\n", siginfo_pkey);
+#if defined(__i386__) || defined(__x86_64__) /* arch */
+	dprintf1("signal pkey_reg from xsave: "PKEY_REG_FMT"\n", *pkey_reg_ptr);
 	*(u64 *)pkey_reg_ptr = 0x00000000;
 	dprintf1("WARNING: set PKEY_REG=0 to allow faulting instruction to continue\n");
+#elif defined(__powerpc64__) /* arch */
+	/* restore access and let the faulting instruction continue */
+	pkey_access_allow(siginfo_pkey);
+#endif /* arch */
 	pkey_faults++;
 	dprintf1("<<<<==================================================\n");
 	dprint_in_signal = 0;
@@ -332,125 +460,6 @@ pid_t fork_lazy_child(void)
 	return forkret;
 }
 
-static u32 hw_pkey_get(int pkey, unsigned long flags)
-{
-	pkey_reg_t pkey_reg = __read_pkey_reg();
-
-	dprintf1("%s(pkey=%d, flags=%lx) = %x / %d\n",
-			__func__, pkey, flags, 0, 0);
-	dprintf2("%s() raw pkey_reg: "PKEY_REG_FMT"\n", __func__, pkey_reg);
-
-	return (u32) get_pkey_bits(pkey_reg, pkey);
-}
-
-static int hw_pkey_set(int pkey, unsigned long rights, unsigned long flags)
-{
-	u32 mask = (PKEY_DISABLE_ACCESS|PKEY_DISABLE_WRITE);
-	pkey_reg_t old_pkey_reg = __read_pkey_reg();
-	pkey_reg_t new_pkey_reg;
-
-	/* make sure that 'rights' only contains the bits we expect: */
-	assert(!(rights & ~mask));
-
-	/* modify bits accordingly in old pkey_reg and assign it */
-	new_pkey_reg = set_pkey_bits(old_pkey_reg, pkey, rights);
-
-	__write_pkey_reg(new_pkey_reg);
-
-	dprintf3("%s(pkey=%d, rights=%lx, flags=%lx) = %x"
-		" pkey_reg now: "PKEY_REG_FMT" old_pkey_reg: "PKEY_REG_FMT"\n",
-		__func__, pkey, rights, flags, 0, __read_pkey_reg(),
-		old_pkey_reg);
-	return 0;
-}
-
-void pkey_disable_set(int pkey, int flags)
-{
-	unsigned long syscall_flags = 0;
-	int ret;
-	int pkey_rights;
-	pkey_reg_t orig_pkey_reg = read_pkey_reg();
-
-	dprintf1("START->%s(%d, 0x%x)\n", __func__,
-		pkey, flags);
-	pkey_assert(flags & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
-
-	pkey_rights = hw_pkey_get(pkey, syscall_flags);
-
-	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
-			pkey, pkey, pkey_rights);
-
-	pkey_assert(pkey_rights >= 0);
-
-	pkey_rights |= flags;
-
-	ret = hw_pkey_set(pkey, pkey_rights, syscall_flags);
-	assert(!ret);
-	/* pkey_reg and flags have the same format */
-	shadow_pkey_reg = set_pkey_bits(shadow_pkey_reg, pkey, pkey_rights);
-	dprintf1("%s(%d) shadow: 0x"PKEY_REG_FMT"\n",
-		__func__, pkey, shadow_pkey_reg);
-
-	pkey_assert(ret >= 0);
-
-	pkey_rights = hw_pkey_get(pkey, syscall_flags);
-	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
-			pkey, pkey, pkey_rights);
-
-	dprintf1("%s(%d) pkey_reg: 0x"PKEY_REG_FMT"\n",
-		__func__, pkey, read_pkey_reg());
-	if (flags)
-		pkey_assert(read_pkey_reg() >= orig_pkey_reg);
-	dprintf1("END<---%s(%d, 0x%x)\n", __func__,
-		pkey, flags);
-}
-
-void pkey_disable_clear(int pkey, int flags)
-{
-	unsigned long syscall_flags = 0;
-	int ret;
-	int pkey_rights = hw_pkey_get(pkey, syscall_flags);
-	pkey_reg_t orig_pkey_reg = read_pkey_reg();
-
-	pkey_assert(flags & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
-
-	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
-			pkey, pkey, pkey_rights);
-	pkey_assert(pkey_rights >= 0);
-
-	pkey_rights &= ~flags;
-
-	ret = hw_pkey_set(pkey, pkey_rights, 0);
-	shadow_pkey_reg = set_pkey_bits(shadow_pkey_reg, pkey, pkey_rights);
-	pkey_assert(ret >= 0);
-
-	pkey_rights = hw_pkey_get(pkey, syscall_flags);
-	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
-			pkey, pkey, pkey_rights);
-
-	dprintf1("%s(%d) pkey_reg: 0x"PKEY_REG_FMT"\n", __func__,
-			pkey, read_pkey_reg());
-	if (flags)
-		assert(read_pkey_reg() <= orig_pkey_reg);
-}
-
-void pkey_write_allow(int pkey)
-{
-	pkey_disable_clear(pkey, PKEY_DISABLE_WRITE);
-}
-void pkey_write_deny(int pkey)
-{
-	pkey_disable_set(pkey, PKEY_DISABLE_WRITE);
-}
-void pkey_access_allow(int pkey)
-{
-	pkey_disable_clear(pkey, PKEY_DISABLE_ACCESS);
-}
-void pkey_access_deny(int pkey)
-{
-	pkey_disable_set(pkey, PKEY_DISABLE_ACCESS);
-}
-
 int sys_mprotect_pkey(void *ptr, size_t size, unsigned long orig_prot,
 		unsigned long pkey)
 {
@@ -889,11 +898,15 @@ void expected_pkey_fault(int pkey)
 	if (pkey != UNKNOWN_PKEY)
 		pkey_assert(last_si_pkey == pkey);
 
+#if defined(__i386__) || defined(__x86_64__) /* arch */
 	/*
 	 * The signal handler shold have cleared out PKEY register to let the
 	 * test program continue.  We now have to restore it.
 	 */
 	if (__read_pkey_reg() != 0)
+#else /* arch */
+	if (__read_pkey_reg() != shadow_pkey_reg)
+#endif /* arch */
 		pkey_assert(0);
 
 	__write_pkey_reg(shadow_pkey_reg);
-- 
2.17.1