[PATCH v3 0/4] Disable compat cruft on ppc64le v3

[PATCH v3 0/4] Disable compat cruft on ppc64le v3

[Michal Suchanek]

Less code means less bugs so add a knob to skip the compat stuff.

This is tested on ppc64le top of

https://patchwork.ozlabs.org/cover/1153556/

Changes in v2: saner CONFIG_COMPAT ifdefs
Changes in v3:
 - change llseek to 32bit instead of builing it unconditionally in fs
 - clanup the makefile conditionals
 - remove some ifdefs or convert to IS_DEFINED where possible

Michal Suchanek (4):
  powerpc: make llseek 32bit-only.
  powerpc: move common register copy functions from signal_32.c to
    signal.c
  powerpc/64: make buildable without CONFIG_COMPAT
  powerpc/64: Make COMPAT user-selectable disable on littleendian by
    default.

 arch/powerpc/Kconfig                     |   5 +-
 arch/powerpc/kernel/Makefile             |   9 +-
 arch/powerpc/kernel/entry_64.S           |   2 +
 arch/powerpc/kernel/signal.c             | 143 ++++++++++++++++++++++-
 arch/powerpc/kernel/signal_32.c          | 140 ----------------------
 arch/powerpc/kernel/syscall_64.c         |   2 +-
 arch/powerpc/kernel/syscalls/syscall.tbl |   2 +-
 arch/powerpc/kernel/vdso.c               |   5 +-
 arch/powerpc/perf/callchain.c            |  13 ++-
 9 files changed, 165 insertions(+), 156 deletions(-)

-- 
2.22.0

[PATCH v3 1/4] powerpc: make llseek 32bit-only.

[Michal Suchanek]

Fixes: aff850393200 ("powerpc: add system call table generation support")

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/kernel/syscalls/syscall.tbl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 010b9f445586..53e427606f6c 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -188,7 +188,7 @@
 137	common	afs_syscall			sys_ni_syscall
 138	common	setfsuid			sys_setfsuid
 139	common	setfsgid			sys_setfsgid
-140	common	_llseek				sys_llseek
+140	32	_llseek				sys_llseek
 141	common	getdents			sys_getdents			compat_sys_getdents
 142	common	_newselect			sys_select			compat_sys_select
 143	common	flock				sys_flock
-- 
2.22.0

[PATCH v3 2/4] powerpc: move common register copy functions from signal_32.c to signal.c

[Michal Suchanek]

These functions are required for 64bit as well.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/kernel/signal.c    | 141 ++++++++++++++++++++++++++++++++
 arch/powerpc/kernel/signal_32.c | 140 -------------------------------
 2 files changed, 141 insertions(+), 140 deletions(-)

diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index e6c30cee6abf..60436432399f 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -18,12 +18,153 @@
 #include <linux/syscalls.h>
 #include <asm/hw_breakpoint.h>
 #include <linux/uaccess.h>
+#include <asm/switch_to.h>
 #include <asm/unistd.h>
 #include <asm/debug.h>
 #include <asm/tm.h>
 
 #include "signal.h"
 
+#ifdef CONFIG_VSX
+unsigned long copy_fpr_to_user(void __user *to,
+			       struct task_struct *task)
+{
+	u64 buf[ELF_NFPREG];
+	int i;
+
+	/* save FPR copy to local buffer then write to the thread_struct */
+	for (i = 0; i < (ELF_NFPREG - 1) ; i++)
+		buf[i] = task->thread.TS_FPR(i);
+	buf[i] = task->thread.fp_state.fpscr;
+	return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
+}
+
+unsigned long copy_fpr_from_user(struct task_struct *task,
+				 void __user *from)
+{
+	u64 buf[ELF_NFPREG];
+	int i;
+
+	if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
+		return 1;
+	for (i = 0; i < (ELF_NFPREG - 1) ; i++)
+		task->thread.TS_FPR(i) = buf[i];
+	task->thread.fp_state.fpscr = buf[i];
+
+	return 0;
+}
+
+unsigned long copy_vsx_to_user(void __user *to,
+			       struct task_struct *task)
+{
+	u64 buf[ELF_NVSRHALFREG];
+	int i;
+
+	/* save FPR copy to local buffer then write to the thread_struct */
+	for (i = 0; i < ELF_NVSRHALFREG; i++)
+		buf[i] = task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET];
+	return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
+}
+
+unsigned long copy_vsx_from_user(struct task_struct *task,
+				 void __user *from)
+{
+	u64 buf[ELF_NVSRHALFREG];
+	int i;
+
+	if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
+		return 1;
+	for (i = 0; i < ELF_NVSRHALFREG ; i++)
+		task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
+	return 0;
+}
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+unsigned long copy_ckfpr_to_user(void __user *to,
+				  struct task_struct *task)
+{
+	u64 buf[ELF_NFPREG];
+	int i;
+
+	/* save FPR copy to local buffer then write to the thread_struct */
+	for (i = 0; i < (ELF_NFPREG - 1) ; i++)
+		buf[i] = task->thread.TS_CKFPR(i);
+	buf[i] = task->thread.ckfp_state.fpscr;
+	return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
+}
+
+unsigned long copy_ckfpr_from_user(struct task_struct *task,
+					  void __user *from)
+{
+	u64 buf[ELF_NFPREG];
+	int i;
+
+	if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
+		return 1;
+	for (i = 0; i < (ELF_NFPREG - 1) ; i++)
+		task->thread.TS_CKFPR(i) = buf[i];
+	task->thread.ckfp_state.fpscr = buf[i];
+
+	return 0;
+}
+
+unsigned long copy_ckvsx_to_user(void __user *to,
+				  struct task_struct *task)
+{
+	u64 buf[ELF_NVSRHALFREG];
+	int i;
+
+	/* save FPR copy to local buffer then write to the thread_struct */
+	for (i = 0; i < ELF_NVSRHALFREG; i++)
+		buf[i] = task->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET];
+	return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
+}
+
+unsigned long copy_ckvsx_from_user(struct task_struct *task,
+					  void __user *from)
+{
+	u64 buf[ELF_NVSRHALFREG];
+	int i;
+
+	if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
+		return 1;
+	for (i = 0; i < ELF_NVSRHALFREG ; i++)
+		task->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
+	return 0;
+}
+#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
+#else
+inline unsigned long copy_fpr_to_user(void __user *to,
+				      struct task_struct *task)
+{
+	return __copy_to_user(to, task->thread.fp_state.fpr,
+			      ELF_NFPREG * sizeof(double));
+}
+
+inline unsigned long copy_fpr_from_user(struct task_struct *task,
+					void __user *from)
+{
+	return __copy_from_user(task->thread.fp_state.fpr, from,
+			      ELF_NFPREG * sizeof(double));
+}
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+inline unsigned long copy_ckfpr_to_user(void __user *to,
+					 struct task_struct *task)
+{
+	return __copy_to_user(to, task->thread.ckfp_state.fpr,
+			      ELF_NFPREG * sizeof(double));
+}
+
+inline unsigned long copy_ckfpr_from_user(struct task_struct *task,
+						 void __user *from)
+{
+	return __copy_from_user(task->thread.ckfp_state.fpr, from,
+				ELF_NFPREG * sizeof(double));
+}
+#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
+#endif
+
 /* Log an error when sending an unhandled signal to a process. Controlled
  * through debug.exception-trace sysctl.
  */
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 98600b276f76..c93c937ea568 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -235,146 +235,6 @@ struct rt_sigframe {
 	int			abigap[56];
 };
 
-#ifdef CONFIG_VSX
-unsigned long copy_fpr_to_user(void __user *to,
-			       struct task_struct *task)
-{
-	u64 buf[ELF_NFPREG];
-	int i;
-
-	/* save FPR copy to local buffer then write to the thread_struct */
-	for (i = 0; i < (ELF_NFPREG - 1) ; i++)
-		buf[i] = task->thread.TS_FPR(i);
-	buf[i] = task->thread.fp_state.fpscr;
-	return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
-}
-
-unsigned long copy_fpr_from_user(struct task_struct *task,
-				 void __user *from)
-{
-	u64 buf[ELF_NFPREG];
-	int i;
-
-	if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
-		return 1;
-	for (i = 0; i < (ELF_NFPREG - 1) ; i++)
-		task->thread.TS_FPR(i) = buf[i];
-	task->thread.fp_state.fpscr = buf[i];
-
-	return 0;
-}
-
-unsigned long copy_vsx_to_user(void __user *to,
-			       struct task_struct *task)
-{
-	u64 buf[ELF_NVSRHALFREG];
-	int i;
-
-	/* save FPR copy to local buffer then write to the thread_struct */
-	for (i = 0; i < ELF_NVSRHALFREG; i++)
-		buf[i] = task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET];
-	return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
-}
-
-unsigned long copy_vsx_from_user(struct task_struct *task,
-				 void __user *from)
-{
-	u64 buf[ELF_NVSRHALFREG];
-	int i;
-
-	if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
-		return 1;
-	for (i = 0; i < ELF_NVSRHALFREG ; i++)
-		task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
-	return 0;
-}
-
-#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
-unsigned long copy_ckfpr_to_user(void __user *to,
-				  struct task_struct *task)
-{
-	u64 buf[ELF_NFPREG];
-	int i;
-
-	/* save FPR copy to local buffer then write to the thread_struct */
-	for (i = 0; i < (ELF_NFPREG - 1) ; i++)
-		buf[i] = task->thread.TS_CKFPR(i);
-	buf[i] = task->thread.ckfp_state.fpscr;
-	return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
-}
-
-unsigned long copy_ckfpr_from_user(struct task_struct *task,
-					  void __user *from)
-{
-	u64 buf[ELF_NFPREG];
-	int i;
-
-	if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
-		return 1;
-	for (i = 0; i < (ELF_NFPREG - 1) ; i++)
-		task->thread.TS_CKFPR(i) = buf[i];
-	task->thread.ckfp_state.fpscr = buf[i];
-
-	return 0;
-}
-
-unsigned long copy_ckvsx_to_user(void __user *to,
-				  struct task_struct *task)
-{
-	u64 buf[ELF_NVSRHALFREG];
-	int i;
-
-	/* save FPR copy to local buffer then write to the thread_struct */
-	for (i = 0; i < ELF_NVSRHALFREG; i++)
-		buf[i] = task->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET];
-	return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
-}
-
-unsigned long copy_ckvsx_from_user(struct task_struct *task,
-					  void __user *from)
-{
-	u64 buf[ELF_NVSRHALFREG];
-	int i;
-
-	if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
-		return 1;
-	for (i = 0; i < ELF_NVSRHALFREG ; i++)
-		task->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
-	return 0;
-}
-#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
-#else
-inline unsigned long copy_fpr_to_user(void __user *to,
-				      struct task_struct *task)
-{
-	return __copy_to_user(to, task->thread.fp_state.fpr,
-			      ELF_NFPREG * sizeof(double));
-}
-
-inline unsigned long copy_fpr_from_user(struct task_struct *task,
-					void __user *from)
-{
-	return __copy_from_user(task->thread.fp_state.fpr, from,
-			      ELF_NFPREG * sizeof(double));
-}
-
-#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
-inline unsigned long copy_ckfpr_to_user(void __user *to,
-					 struct task_struct *task)
-{
-	return __copy_to_user(to, task->thread.ckfp_state.fpr,
-			      ELF_NFPREG * sizeof(double));
-}
-
-inline unsigned long copy_ckfpr_from_user(struct task_struct *task,
-						 void __user *from)
-{
-	return __copy_from_user(task->thread.ckfp_state.fpr, from,
-				ELF_NFPREG * sizeof(double));
-}
-#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
-#endif
-
 /*
  * Save the current user registers on the user stack.
  * We only save the altivec/spe registers if the process has used
-- 
2.22.0

[PATCH v3 3/4] powerpc/64: make buildable without CONFIG_COMPAT

[Michal Suchanek]

There are numerous references to 32bit functions in generic and 64bit
code so ifdef them out.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
v2:
- fix 32bit ifdef condition in signal.c
- simplify the compat ifdef condition in vdso.c - 64bit is redundant
- simplify the compat ifdef condition in callchain.c - 64bit is redundant
v3:
- use IS_ENABLED and maybe_unused where possible
- do not ifdef declarations
- clean up Makefile
---
 arch/powerpc/kernel/Makefile     |  9 +++++----
 arch/powerpc/kernel/entry_64.S   |  2 ++
 arch/powerpc/kernel/signal.c     |  2 +-
 arch/powerpc/kernel/syscall_64.c |  2 +-
 arch/powerpc/kernel/vdso.c       |  5 ++---
 arch/powerpc/perf/callchain.c    | 13 +++++++++----
 6 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 1d646a94d96c..de1fbb21daf5 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -44,16 +44,17 @@ CFLAGS_btext.o += -DDISABLE_BRANCH_PROFILING
 endif
 
 obj-y				:= cputable.o ptrace.o syscalls.o \
-				   irq.o align.o signal_32.o pmc.o vdso.o \
+				   irq.o align.o signal_$(BITS).o pmc.o vdso.o \
 				   process.o systbl.o idle.o \
 				   signal.o sysfs.o cacheinfo.o time.o \
 				   prom.o traps.o setup-common.o \
 				   udbg.o misc.o io.o misc_$(BITS).o \
 				   of_platform.o prom_parse.o
-obj-$(CONFIG_PPC64)		+= setup_64.o sys_ppc32.o \
-				   signal_64.o ptrace32.o \
-				   paca.o nvram_64.o firmware.o \
+obj-$(CONFIG_PPC64)		+= setup_64.o paca.o nvram_64.o firmware.o \
 				   syscall_64.o
+ifdef CONFIG_COMPAT
+obj-y				+= sys_ppc32.o ptrace32.o signal_32.o
+endif
 obj-$(CONFIG_VDSO32)		+= vdso32/
 obj-$(CONFIG_PPC_WATCHDOG)	+= watchdog.o
 obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 2ec825a85f5b..a2dbf216f607 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -51,8 +51,10 @@
 SYS_CALL_TABLE:
 	.tc sys_call_table[TC],sys_call_table
 
+#ifdef CONFIG_COMPAT
 COMPAT_SYS_CALL_TABLE:
 	.tc compat_sys_call_table[TC],compat_sys_call_table
+#endif
 
 /* This value is used to mark exception frames on the stack. */
 exception_marker:
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index 60436432399f..73d0f53ffc1a 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -277,7 +277,7 @@ static void do_signal(struct task_struct *tsk)
 
 	rseq_signal_deliver(&ksig, tsk->thread.regs);
 
-	if (is32) {
+	if ((IS_ENABLED(CONFIG_PPC32) || IS_ENABLED(CONFIG_COMPAT)) && is32) {
         	if (ksig.ka.sa.sa_flags & SA_SIGINFO)
 			ret = handle_rt_signal32(&ksig, oldset, tsk);
 		else
diff --git a/arch/powerpc/kernel/syscall_64.c b/arch/powerpc/kernel/syscall_64.c
index 98ed970796d5..bdd9dcf156f8 100644
--- a/arch/powerpc/kernel/syscall_64.c
+++ b/arch/powerpc/kernel/syscall_64.c
@@ -100,7 +100,7 @@ long system_call_exception(long r3, long r4, long r5, long r6, long r7, long r8,
 	/* May be faster to do array_index_nospec? */
 	barrier_nospec();
 
-	if (unlikely(ti_flags & _TIF_32BIT)) {
+	if (IS_ENABLED(CONFIG_COMPAT) && unlikely(ti_flags & _TIF_32BIT)) {
 		f = (void *)compat_sys_call_table[r0];
 
 		r3 &= 0x00000000ffffffffULL;
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index d60598113a9f..6d4a077f74d6 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -667,9 +667,7 @@ static void __init vdso_setup_syscall_map(void)
 {
 	unsigned int i;
 	extern unsigned long *sys_call_table;
-#ifdef CONFIG_PPC64
 	extern unsigned long *compat_sys_call_table;
-#endif
 	extern unsigned long sys_ni_syscall;
 
 
@@ -678,7 +676,8 @@ static void __init vdso_setup_syscall_map(void)
 		if (sys_call_table[i] != sys_ni_syscall)
 			vdso_data->syscall_map_64[i >> 5] |=
 				0x80000000UL >> (i & 0x1f);
-		if (compat_sys_call_table[i] != sys_ni_syscall)
+		if (IS_ENABLED(CONFIG_COMPAT) &&
+		    compat_sys_call_table[i] != sys_ni_syscall)
 			vdso_data->syscall_map_32[i >> 5] |=
 				0x80000000UL >> (i & 0x1f);
 #else /* CONFIG_PPC64 */
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index c84bbd4298a0..d4e6bf22e0cc 100644
--- a/arch/powerpc/perf/callchain.c
+++ b/arch/powerpc/perf/callchain.c
@@ -15,7 +15,7 @@
 #include <asm/sigcontext.h>
 #include <asm/ucontext.h>
 #include <asm/vdso.h>
-#ifdef CONFIG_PPC64
+#ifdef CONFIG_COMPAT
 #include "../kernel/ppc32.h"
 #endif
 #include <asm/pte-walk.h>
@@ -165,6 +165,7 @@ static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)
 	return read_user_stack_slow(ptr, ret, 8);
 }
 
+__maybe_unused
 static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
 {
 	if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
@@ -341,6 +342,7 @@ static inline int valid_user_sp(unsigned long sp, int is_64)
 
 #endif /* CONFIG_PPC64 */
 
+#if defined(CONFIG_PPC32) || defined(CONFIG_COMPAT)
 /*
  * Layout for non-RT signal frames
  */
@@ -482,12 +484,15 @@ static void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry,
 		sp = next_sp;
 	}
 }
+#endif /* 32bit */
 
 void
 perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
 {
-	if (current_is_64bit())
-		perf_callchain_user_64(entry, regs);
-	else
+#if defined(CONFIG_PPC32) || defined(CONFIG_COMPAT)
+	if (!current_is_64bit())
 		perf_callchain_user_32(entry, regs);
+	else
+#endif
+		perf_callchain_user_64(entry, regs);
 }
-- 
2.22.0

[PATCH v3 4/4] powerpc/64: Make COMPAT user-selectable disabled on littleendian by default.

[Michal Suchanek]

On bigendian ppc64 it is common to have 32bit legacy binaries but much
less so on littleendian.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
v3: make configurable
---
 arch/powerpc/Kconfig | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 5bab0bb6b833..b0339e892329 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -264,8 +264,9 @@ config PANIC_TIMEOUT
 	default 180
 
 config COMPAT
-	bool
-	default y if PPC64
+	bool "Enable support for 32bit binaries"
+	depends on PPC64
+	default y if !CPU_LITTLE_ENDIAN
 	select COMPAT_BINFMT_ELF
 	select ARCH_WANT_OLD_COMPAT_IPC
 	select COMPAT_OLD_SIGACTION
-- 
2.22.0

Re: [PATCH v3 3/4] powerpc/64: make buildable without CONFIG_COMPAT

[Christoph Hellwig]

On Wed, Aug 28, 2019 at 06:43:50PM +0200, Michal Suchanek wrote:
> +ifdef CONFIG_COMPAT
> +obj-y				+= sys_ppc32.o ptrace32.o signal_32.o
> +endif

This should be:

obj-$(CONFIG_COMPAT)		+= sys_ppc32.o ptrace32.o signal_32.o

>  /* This value is used to mark exception frames on the stack. */
>  exception_marker:
> diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
> index 60436432399f..73d0f53ffc1a 100644
> --- a/arch/powerpc/kernel/signal.c
> +++ b/arch/powerpc/kernel/signal.c
> @@ -277,7 +277,7 @@ static void do_signal(struct task_struct *tsk)
>  
>  	rseq_signal_deliver(&ksig, tsk->thread.regs);
>  
> -	if (is32) {
> +	if ((IS_ENABLED(CONFIG_PPC32) || IS_ENABLED(CONFIG_COMPAT)) && is32) {

I think we should fix the is_32bit_task definitions instead so that
callers don't need this mess.  I'd suggest something like:

#ifdef CONFIG_COMPAT
#define is_32bit_task()		test_thread_flag(TIF_32BIT)
#else
#define is_32bit_task()		IS_ENABLED(CONFIG_PPC32)
#endif

Re: [PATCH v3 3/4] powerpc/64: make buildable without CONFIG_COMPAT

[Arnd Bergmann]

On Thu, Aug 29, 2019 at 8:46 AM Christoph Hellwig <hch@infradead.org> wrote:

> > @@ -277,7 +277,7 @@ static void do_signal(struct task_struct *tsk)
> >
> >       rseq_signal_deliver(&ksig, tsk->thread.regs);
> >
> > -     if (is32) {
> > +     if ((IS_ENABLED(CONFIG_PPC32) || IS_ENABLED(CONFIG_COMPAT)) && is32) {
>
> I think we should fix the is_32bit_task definitions instead so that
> callers don't need this mess.  I'd suggest something like:
>
> #ifdef CONFIG_COMPAT
> #define is_32bit_task()         test_thread_flag(TIF_32BIT)
> #else
> #define is_32bit_task()         IS_ENABLED(CONFIG_PPC32)
> #endif

Are there actually any (correct) uses of is_32bit_task() outside of
#ifdef CONFIG_PPC64?

I suspect most if not all could be changed to the generic
in_compat_syscall() that we use outside of architecture specific
code.

       Arnd

Re: [PATCH v3 3/4] powerpc/64: make buildable without CONFIG_COMPAT

[Christophe Leroy]

Le 29/08/2019 à 10:01, Arnd Bergmann a écrit :
> On Thu, Aug 29, 2019 at 8:46 AM Christoph Hellwig <hch@infradead.org> wrote:
> 
>>> @@ -277,7 +277,7 @@ static void do_signal(struct task_struct *tsk)
>>>
>>>        rseq_signal_deliver(&ksig, tsk->thread.regs);
>>>
>>> -     if (is32) {
>>> +     if ((IS_ENABLED(CONFIG_PPC32) || IS_ENABLED(CONFIG_COMPAT)) && is32) {
>>
>> I think we should fix the is_32bit_task definitions instead so that
>> callers don't need this mess.  I'd suggest something like:
>>
>> #ifdef CONFIG_COMPAT
>> #define is_32bit_task()         test_thread_flag(TIF_32BIT)
>> #else
>> #define is_32bit_task()         IS_ENABLED(CONFIG_PPC32)
>> #endif
> 
> Are there actually any (correct) uses of is_32bit_task() outside of
> #ifdef CONFIG_PPC64?

There is at least  stack_maxrandom_size()
Also  brk_rnd() and do_signal()

Christophe

> 
> I suspect most if not all could be changed to the generic
> in_compat_syscall() that we use outside of architecture specific
> code.
> 
>         Arnd
> 

Re: [PATCH v3 3/4] powerpc/64: make buildable without CONFIG_COMPAT

[Arnd Bergmann]

On Thu, Aug 29, 2019 at 10:38 AM Christophe Leroy
<christophe.leroy@c-s.fr> wrote:
> Le 29/08/2019 à 10:01, Arnd Bergmann a écrit :
> > On Thu, Aug 29, 2019 at 8:46 AM Christoph Hellwig <hch@infradead.org> wrote:
> >
> >>> @@ -277,7 +277,7 @@ static void do_signal(struct task_struct *tsk)
> >>>
> >>>        rseq_signal_deliver(&ksig, tsk->thread.regs);
> >>>
> >>> -     if (is32) {
> >>> +     if ((IS_ENABLED(CONFIG_PPC32) || IS_ENABLED(CONFIG_COMPAT)) && is32) {
> >>
> >> I think we should fix the is_32bit_task definitions instead so that
> >> callers don't need this mess.  I'd suggest something like:
> >>
> >> #ifdef CONFIG_COMPAT
> >> #define is_32bit_task()         test_thread_flag(TIF_32BIT)
> >> #else
> >> #define is_32bit_task()         IS_ENABLED(CONFIG_PPC32)
> >> #endif
> >
> > Are there actually any (correct) uses of is_32bit_task() outside of
> > #ifdef CONFIG_PPC64?
>
> There is at least  stack_maxrandom_size()
> Also  brk_rnd() and do_signal()

Right, makes sense.

      Arnd

Re: [PATCH v3 3/4] powerpc/64: make buildable without CONFIG_COMPAT

[Michal Suchánek]

On Wed, 28 Aug 2019 23:46:24 -0700
Christoph Hellwig <hch@infradead.org> wrote:

> On Wed, Aug 28, 2019 at 06:43:50PM +0200, Michal Suchanek wrote:
> > +ifdef CONFIG_COMPAT
> > +obj-y				+= sys_ppc32.o ptrace32.o signal_32.o
> > +endif  
> 
> This should be:
> 
> obj-$(CONFIG_COMPAT)		+= sys_ppc32.o ptrace32.o signal_32.o

Yes, looks better.
> 
> >  /* This value is used to mark exception frames on the stack. */
> >  exception_marker:
> > diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
> > index 60436432399f..73d0f53ffc1a 100644
> > --- a/arch/powerpc/kernel/signal.c
> > +++ b/arch/powerpc/kernel/signal.c
> > @@ -277,7 +277,7 @@ static void do_signal(struct task_struct *tsk)
> >  
> >  	rseq_signal_deliver(&ksig, tsk->thread.regs);
> >  
> > -	if (is32) {
> > +	if ((IS_ENABLED(CONFIG_PPC32) || IS_ENABLED(CONFIG_COMPAT)) && is32) {  
> 
> I think we should fix the is_32bit_task definitions instead so that
> callers don't need this mess.  

Yes, that makes sense.

Thanks

Michal