diff mbox

[11/18] arm64: ilp32: share aarch32 syscall handlers

Message ID 1477081997-4770-12-git-send-email-ynorov@caviumnetworks.com (mailing list archive)
State New, archived
Headers show

Commit Message

Yury Norov Oct. 21, 2016, 8:33 p.m. UTC 
off_t is  passed in register pair just like in aarch32.
In this patch corresponding aarch32 handlers are shared to
ilp32 code.

Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
---
 arch/arm64/kernel/Makefile         |   1 +
 arch/arm64/kernel/entry32.S        |  80 ---------------------------
 arch/arm64/kernel/entry32_common.S | 107 +++++++++++++++++++++++++++++++++++++
 3 files changed, 108 insertions(+), 80 deletions(-)
 create mode 100644 arch/arm64/kernel/entry32_common.S

Comments

Catalin Marinas Dec. 5, 2016, 5:12 p.m. UTC | #1 
On Fri, Oct 21, 2016 at 11:33:10PM +0300, Yury Norov wrote:
> off_t is  passed in register pair just like in aarch32.
> In this patch corresponding aarch32 handlers are shared to
> ilp32 code.
[...]
> +/*
> + * Note: off_4k (w5) is always in units of 4K. If we can't do the
> + * requested offset because it is not page-aligned, we return -EINVAL.
> + */
> +ENTRY(compat_sys_mmap2_wrapper)
> +#if PAGE_SHIFT > 12
> +	tst	w5, #~PAGE_MASK >> 12
> +	b.ne	1f
> +	lsr	w5, w5, #PAGE_SHIFT - 12
> +#endif
> +	b	sys_mmap_pgoff
> +1:	mov	x0, #-EINVAL
> +	ret
> +ENDPROC(compat_sys_mmap2_wrapper)

For compat sys_mmap2, the pgoff argument is in multiples of 4K. This was
traditionally used for architectures where off_t is 32-bit to allow
mapping files to 2^44.

Since off_t is 64-bit with AArch64/ILP32, should we just pass the off_t
as a 64-bit value in two different registers (w5 and w6)?
Yury Norov Dec. 6, 2016, 7:32 a.m. UTC | #2 
On Mon, Dec 05, 2016 at 05:12:43PM +0000, Catalin Marinas wrote:
> On Fri, Oct 21, 2016 at 11:33:10PM +0300, Yury Norov wrote:
> > off_t is  passed in register pair just like in aarch32.
> > In this patch corresponding aarch32 handlers are shared to
> > ilp32 code.
> [...]
> > +/*
> > + * Note: off_4k (w5) is always in units of 4K. If we can't do the
> > + * requested offset because it is not page-aligned, we return -EINVAL.
> > + */
> > +ENTRY(compat_sys_mmap2_wrapper)
> > +#if PAGE_SHIFT > 12
> > +	tst	w5, #~PAGE_MASK >> 12
> > +	b.ne	1f
> > +	lsr	w5, w5, #PAGE_SHIFT - 12
> > +#endif
> > +	b	sys_mmap_pgoff
> > +1:	mov	x0, #-EINVAL
> > +	ret
> > +ENDPROC(compat_sys_mmap2_wrapper)
> 
> For compat sys_mmap2, the pgoff argument is in multiples of 4K. This was
> traditionally used for architectures where off_t is 32-bit to allow
> mapping files to 2^44.
> 
> Since off_t is 64-bit with AArch64/ILP32, should we just pass the off_t
> as a 64-bit value in two different registers (w5 and w6)?

Current glibc implementation becomes broken for 64-bit off_t if
if I'll do what you want.
sysdeps/unix/sysv/linux/generic/wordsize-32/mmap.c
28 __ptr_t
29 __mmap (__ptr_t addr, size_t len, int prot, int flags, int fd, off_t offset)
30 {
31   if (offset & (MMAP_PAGE_UNIT - 1))
32     {
33       __set_errno (EINVAL);
34       return MAP_FAILED;
35     }
36   return (__ptr_t) INLINE_SYSCALL (mmap2, 6, addr, len, prot, flags, fd,
37                                    offset / MMAP_PAGE_UNIT);
38 }
39 
40 weak_alias (__mmap, mmap)

So it requires changes both in glibc and in kernel. I can do it. But
I'd like to collect opinions of kernel and glibc developers before
starting it. 

Yury
diff mbox

Patch

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index f661888..9123bb8 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -30,6 +30,7 @@  $(obj)/%.stub.o: $(obj)/%.o FORCE
 arm64-obj-$(CONFIG_AARCH32_EL0)		+= sys32.o kuser32.o signal32.o 	\
 					   sys_compat.o entry32.o binfmt_elf32.o
 arm64-obj-$(CONFIG_ARM64_ILP32)		+= binfmt_ilp32.o
+arm64-obj-$(CONFIG_COMPAT)		+= entry32_common.o
 arm64-obj-$(CONFIG_FUNCTION_TRACER)	+= ftrace.o entry-ftrace.o
 arm64-obj-$(CONFIG_MODULES)		+= arm64ksyms.o module.o
 arm64-obj-$(CONFIG_ARM64_MODULE_PLTS)	+= module-plts.o
diff --git a/arch/arm64/kernel/entry32.S b/arch/arm64/kernel/entry32.S
index f332d5d..4bede03 100644
--- a/arch/arm64/kernel/entry32.S
+++ b/arch/arm64/kernel/entry32.S
@@ -39,83 +39,3 @@  ENTRY(compat_sys_rt_sigreturn_wrapper)
 	mov	x0, sp
 	b	compat_sys_rt_sigreturn
 ENDPROC(compat_sys_rt_sigreturn_wrapper)
-
-ENTRY(compat_sys_statfs64_wrapper)
-	mov	w3, #84
-	cmp	w1, #88
-	csel	w1, w3, w1, eq
-	b	compat_sys_statfs64
-ENDPROC(compat_sys_statfs64_wrapper)
-
-ENTRY(compat_sys_fstatfs64_wrapper)
-	mov	w3, #84
-	cmp	w1, #88
-	csel	w1, w3, w1, eq
-	b	compat_sys_fstatfs64
-ENDPROC(compat_sys_fstatfs64_wrapper)
-
-/*
- * Note: off_4k (w5) is always in units of 4K. If we can't do the
- * requested offset because it is not page-aligned, we return -EINVAL.
- */
-ENTRY(compat_sys_mmap2_wrapper)
-#if PAGE_SHIFT > 12
-	tst	w5, #~PAGE_MASK >> 12
-	b.ne	1f
-	lsr	w5, w5, #PAGE_SHIFT - 12
-#endif
-	b	sys_mmap_pgoff
-1:	mov	x0, #-EINVAL
-	ret
-ENDPROC(compat_sys_mmap2_wrapper)
-
-/*
- * Wrappers for AArch32 syscalls that either take 64-bit parameters
- * in registers or that take 32-bit parameters which require sign
- * extension.
- */
-ENTRY(compat_sys_pread64_wrapper)
-	regs_to_64	x3, x4, x5
-	b	sys_pread64
-ENDPROC(compat_sys_pread64_wrapper)
-
-ENTRY(compat_sys_pwrite64_wrapper)
-	regs_to_64	x3, x4, x5
-	b	sys_pwrite64
-ENDPROC(compat_sys_pwrite64_wrapper)
-
-ENTRY(compat_sys_truncate64_wrapper)
-	regs_to_64	x1, x2, x3
-	b	sys_truncate
-ENDPROC(compat_sys_truncate64_wrapper)
-
-ENTRY(compat_sys_ftruncate64_wrapper)
-	regs_to_64	x1, x2, x3
-	b	sys_ftruncate
-ENDPROC(compat_sys_ftruncate64_wrapper)
-
-ENTRY(compat_sys_readahead_wrapper)
-	regs_to_64	x1, x2, x3
-	mov	w2, w4
-	b	sys_readahead
-ENDPROC(compat_sys_readahead_wrapper)
-
-ENTRY(compat_sys_fadvise64_64_wrapper)
-	mov	w6, w1
-	regs_to_64	x1, x2, x3
-	regs_to_64	x2, x4, x5
-	mov	w3, w6
-	b	sys_fadvise64_64
-ENDPROC(compat_sys_fadvise64_64_wrapper)
-
-ENTRY(compat_sys_sync_file_range2_wrapper)
-	regs_to_64	x2, x2, x3
-	regs_to_64	x3, x4, x5
-	b	sys_sync_file_range2
-ENDPROC(compat_sys_sync_file_range2_wrapper)
-
-ENTRY(compat_sys_fallocate_wrapper)
-	regs_to_64	x2, x2, x3
-	regs_to_64	x3, x4, x5
-	b	sys_fallocate
-ENDPROC(compat_sys_fallocate_wrapper)
diff --git a/arch/arm64/kernel/entry32_common.S b/arch/arm64/kernel/entry32_common.S
new file mode 100644
index 0000000..f4a5e4d
--- /dev/null
+++ b/arch/arm64/kernel/entry32_common.S
@@ -0,0 +1,107 @@ 
+/*
+ * Compat system call wrappers
+ *
+ * Copyright (C) 2012 ARM Ltd.
+ * Authors: Will Deacon <will.deacon@arm.com>
+ *	    Catalin Marinas <catalin.marinas@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/linkage.h>
+#include <linux/const.h>
+
+#include <asm/assembler.h>
+#include <asm/asm-offsets.h>
+#include <asm/errno.h>
+#include <asm/page.h>
+
+/*
+ * Note: off_4k (w5) is always in units of 4K. If we can't do the
+ * requested offset because it is not page-aligned, we return -EINVAL.
+ */
+ENTRY(compat_sys_mmap2_wrapper)
+#if PAGE_SHIFT > 12
+	tst	w5, #~PAGE_MASK >> 12
+	b.ne	1f
+	lsr	w5, w5, #PAGE_SHIFT - 12
+#endif
+	b	sys_mmap_pgoff
+1:	mov	x0, #-EINVAL
+	ret
+ENDPROC(compat_sys_mmap2_wrapper)
+
+/*
+ * Wrappers for AArch32 syscalls that either take 64-bit parameters
+ * in registers or that take 32-bit parameters which require sign
+ * extension.
+ */
+ENTRY(compat_sys_pread64_wrapper)
+	regs_to_64	x3, x4, x5
+	b	sys_pread64
+ENDPROC(compat_sys_pread64_wrapper)
+
+ENTRY(compat_sys_pwrite64_wrapper)
+	regs_to_64	x3, x4, x5
+	b	sys_pwrite64
+ENDPROC(compat_sys_pwrite64_wrapper)
+
+ENTRY(compat_sys_truncate64_wrapper)
+	regs_to_64	x1, x2, x3
+	b	sys_truncate
+ENDPROC(compat_sys_truncate64_wrapper)
+
+ENTRY(compat_sys_ftruncate64_wrapper)
+	regs_to_64	x1, x2, x3
+	b	sys_ftruncate
+ENDPROC(compat_sys_ftruncate64_wrapper)
+
+ENTRY(compat_sys_readahead_wrapper)
+	regs_to_64	x1, x2, x3
+	mov	w2, w4
+	b	sys_readahead
+ENDPROC(compat_sys_readahead_wrapper)
+
+ENTRY(compat_sys_fadvise64_64_wrapper)
+	mov	w6, w1
+	regs_to_64	x1, x2, x3
+	regs_to_64	x2, x4, x5
+	mov	w3, w6
+	b	sys_fadvise64_64
+ENDPROC(compat_sys_fadvise64_64_wrapper)
+
+ENTRY(compat_sys_sync_file_range2_wrapper)
+	regs_to_64	x2, x2, x3
+	regs_to_64	x3, x4, x5
+	b	sys_sync_file_range2
+ENDPROC(compat_sys_sync_file_range2_wrapper)
+
+ENTRY(compat_sys_fallocate_wrapper)
+	regs_to_64	x2, x2, x3
+	regs_to_64	x3, x4, x5
+	b	sys_fallocate
+ENDPROC(compat_sys_fallocate_wrapper)
+
+ENTRY(compat_sys_statfs64_wrapper)
+	mov	w3, #84
+	cmp	w1, #88
+	csel	w1, w3, w1, eq
+	b	compat_sys_statfs64
+ENDPROC(compat_sys_statfs64_wrapper)
+
+ENTRY(compat_sys_fstatfs64_wrapper)
+	mov	w3, #84
+	cmp	w1, #88
+	csel	w1, w3, w1, eq
+	b	compat_sys_fstatfs64
+ENDPROC(compat_sys_fstatfs64_wrapper)