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From: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, will.deacon@arm.com
Cc: catalin.marinas@arm.com, dave.martin@arm.com, hch@infradead.org,
	james.morse@arm.com, linux@dominikbrodowski.net,
	linux-fsdevel@vger.kernel.org, marc.zyngier@arm.com,
	mark.rutland@arm.com, viro@zeniv.linux.org.uk
Subject: [PATCHv5 14/21] arm64: drop alignment from syscall tables
Date: Wed, 11 Jul 2018 14:56:49 +0100	[thread overview]
Message-ID: <20180711135656.20670-15-mark.rutland@arm.com> (raw)
In-Reply-To: <20180711135656.20670-1-mark.rutland@arm.com>

Our syscall tables are aligned to 4096 bytes, which allowed their
addresses to be generated with a single adrp in entry.S. This has the
unfortunate property of wasting space in .rodata for the necessary
padding.

Now that the address is generated by C code, we can rely on the compiler
to do the right thing, and drop the alignemnt.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/kernel/sys.c   | 6 +-----
 arch/arm64/kernel/sys32.c | 6 +-----
 2 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kernel/sys.c b/arch/arm64/kernel/sys.c
index 7f0907261269..df8180175515 100644
--- a/arch/arm64/kernel/sys.c
+++ b/arch/arm64/kernel/sys.c
@@ -56,11 +56,7 @@ asmlinkage long sys_rt_sigreturn(void);
 #undef __SYSCALL
 #define __SYSCALL(nr, sym)	[nr] = (syscall_fn_t)sym,
 
-/*
- * The sys_call_table array must be 4K aligned to be accessible from
- * kernel/entry.S.
- */
-const syscall_fn_t sys_call_table[__NR_syscalls] __aligned(4096) = {
+const syscall_fn_t sys_call_table[__NR_syscalls] = {
 	[0 ... __NR_syscalls - 1] = (syscall_fn_t)sys_ni_syscall,
 #include <asm/unistd.h>
 };
diff --git a/arch/arm64/kernel/sys32.c b/arch/arm64/kernel/sys32.c
index d993214118aa..4ddeaae90128 100644
--- a/arch/arm64/kernel/sys32.c
+++ b/arch/arm64/kernel/sys32.c
@@ -44,11 +44,7 @@ asmlinkage long compat_sys_mmap2_wrapper(void);
 #undef __SYSCALL
 #define __SYSCALL(nr, sym)	[nr] = (syscall_fn_t)sym,
 
-/*
- * The sys_call_table array must be 4K aligned to be accessible from
- * kernel/entry.S.
- */
-const syscall_fn_t compat_sys_call_table[__NR_compat_syscalls] __aligned(4096) = {
+const syscall_fn_t compat_sys_call_table[__NR_compat_syscalls] = {
 	[0 ... __NR_compat_syscalls - 1] = (syscall_fn_t)sys_ni_syscall,
 #include <asm/unistd32.h>
 };
-- 
2.11.0


WARNING: multiple messages have this Message-ID (diff)
From: mark.rutland@arm.com (Mark Rutland)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCHv5 14/21] arm64: drop alignment from syscall tables
Date: Wed, 11 Jul 2018 14:56:49 +0100	[thread overview]
Message-ID: <20180711135656.20670-15-mark.rutland@arm.com> (raw)
In-Reply-To: <20180711135656.20670-1-mark.rutland@arm.com>

Our syscall tables are aligned to 4096 bytes, which allowed their
addresses to be generated with a single adrp in entry.S. This has the
unfortunate property of wasting space in .rodata for the necessary
padding.

Now that the address is generated by C code, we can rely on the compiler
to do the right thing, and drop the alignemnt.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/kernel/sys.c   | 6 +-----
 arch/arm64/kernel/sys32.c | 6 +-----
 2 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kernel/sys.c b/arch/arm64/kernel/sys.c
index 7f0907261269..df8180175515 100644
--- a/arch/arm64/kernel/sys.c
+++ b/arch/arm64/kernel/sys.c
@@ -56,11 +56,7 @@ asmlinkage long sys_rt_sigreturn(void);
 #undef __SYSCALL
 #define __SYSCALL(nr, sym)	[nr] = (syscall_fn_t)sym,
 
-/*
- * The sys_call_table array must be 4K aligned to be accessible from
- * kernel/entry.S.
- */
-const syscall_fn_t sys_call_table[__NR_syscalls] __aligned(4096) = {
+const syscall_fn_t sys_call_table[__NR_syscalls] = {
 	[0 ... __NR_syscalls - 1] = (syscall_fn_t)sys_ni_syscall,
 #include <asm/unistd.h>
 };
diff --git a/arch/arm64/kernel/sys32.c b/arch/arm64/kernel/sys32.c
index d993214118aa..4ddeaae90128 100644
--- a/arch/arm64/kernel/sys32.c
+++ b/arch/arm64/kernel/sys32.c
@@ -44,11 +44,7 @@ asmlinkage long compat_sys_mmap2_wrapper(void);
 #undef __SYSCALL
 #define __SYSCALL(nr, sym)	[nr] = (syscall_fn_t)sym,
 
-/*
- * The sys_call_table array must be 4K aligned to be accessible from
- * kernel/entry.S.
- */
-const syscall_fn_t compat_sys_call_table[__NR_compat_syscalls] __aligned(4096) = {
+const syscall_fn_t compat_sys_call_table[__NR_compat_syscalls] = {
 	[0 ... __NR_compat_syscalls - 1] = (syscall_fn_t)sys_ni_syscall,
 #include <asm/unistd32.h>
 };
-- 
2.11.0

  parent reply	other threads:[~2018-07-11 13:57 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-11 13:56 [PATCHv5 00/21] arm64: invoke syscalls with pt_regs Mark Rutland
2018-07-11 13:56 ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 01/21] arm64: consistently use unsigned long for thread flags Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 02/21] arm64: move SCTLR_EL{1,2} assertions to <asm/sysreg.h> Mark Rutland
2018-07-11 13:56   ` [PATCHv5 02/21] arm64: move SCTLR_EL{1, 2} " Mark Rutland
2018-07-11 13:56 ` [PATCHv5 03/21] arm64: kill config_sctlr_el1() Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 04/21] arm64: kill change_cpacr() Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 05/21] arm64: move sve_user_{enable,disable} to <asm/fpsimd.h> Mark Rutland
2018-07-11 13:56   ` [PATCHv5 05/21] arm64: move sve_user_{enable, disable} " Mark Rutland
2018-07-11 13:56 ` [PATCHv5 06/21] arm64: remove sigreturn wrappers Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 07/21] arm64: introduce syscall_fn_t Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 08/21] arm64: convert raw syscall invocation to C Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 09/21] arm64: convert syscall trace logic " Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 10/21] arm64: convert native/compat syscall entry " Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 11/21] arm64: don't restore GPRs when context tracking Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 12/21] arm64: don't reload GPRs after apply_ssbd Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 13/21] arm64: zero GPRs upon entry from EL0 Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` Mark Rutland [this message]
2018-07-11 13:56   ` [PATCHv5 14/21] arm64: drop alignment from syscall tables Mark Rutland
2018-07-11 13:56 ` [PATCHv5 15/21] kernel: add ksys_personality() Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 16/21] kernel: add kcompat_sys_{f,}statfs64() Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 17/21] arm64: remove in-kernel call to sys_personality() Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 18/21] arm64: use {COMPAT,}SYSCALL_DEFINE0 for sigreturn Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 19/21] arm64: use SYSCALL_DEFINE6() for mmap Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 20/21] arm64: convert compat wrappers to C Mark Rutland
2018-07-11 13:56   ` Mark Rutland
2018-07-11 13:56 ` [PATCHv5 21/21] arm64: implement syscall wrappers Mark Rutland
2018-07-11 13:56   ` Mark Rutland

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