2
0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-23 20:53:53 +08:00
linux-next/arch
Nicolas Pitre 2d2669b629 [PATCH] ARM: 2651/3: kernel helpers for NPTL support
Patch from Nicolas Pitre

This patch entirely reworks the kernel assistance for NPTL on ARM.
In particular this provides an efficient way to retrieve the TLS
value and perform atomic operations without any instruction emulation
nor special system call.  This even allows for pre ARMv6 binaries to
be forward compatible with SMP systems without any penalty.
The problematic and performance critical operations are performed
through segment of kernel provided user code reachable from user space
at a fixed address in kernel memory.  Those fixed entry points are
within the vector page so we basically get it for free as no extra
memory page is required and nothing else may be mapped at that
location anyway.
This is different from (but doesn't preclude) a full blown VDSO
implementation, however a VDSO would prevent some assembly tricks with
constants that allows for efficient branching to those code segments.
And since those code segments only use a few cycles before returning to
user code, the overhead of a VDSO far call would add a significant
overhead to such minimalistic operations.
The ARM_NR_set_tls syscall also changed number.  This is done for two
reasons:
1) this patch changes the way the TLS value was previously meant to be
   retrieved, therefore we ensure whatever library using the old way
   gets fixed (they only exist in private tree at the moment since the
   NPTL work is still progressing).
2) the previous number was allocated in a range causing an undefined
   instruction trap on kernels not supporting that syscall and it was
   determined that allocating it in a range returning -ENOSYS would be
   much nicer for libraries trying to determine if the feature is
   present or not.

Signed-off-by: Nicolas Pitre
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-04-29 22:08:33 +01:00
..
alpha [PATCH] alpha: key management syscalls 2005-04-21 11:28:26 -07:00
arm [PATCH] ARM: 2651/3: kernel helpers for NPTL support 2005-04-29 22:08:33 +01:00
arm26 [PATCH] freepgt: arm26 FIRST_USER_ADDRESS PAGE_SIZE 2005-04-19 13:29:22 -07:00
cris Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
frv Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
h8300 Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
i386 [PATCH] fix subarch breakage in amd dual core updates 2005-04-21 16:20:35 -07:00
ia64 From: jbarnes@sgi.com 2005-04-25 13:31:04 -07:00
m32r Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
m68k [PATCH] M68k: Update defconfigs for 2.6.12-rc2 2005-04-18 10:47:34 -07:00
m68knommu Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mips [PATCH] mips: remove #include <linux/audit.h> two times 2005-04-16 15:24:41 -07:00
parisc [PATCH] add Big Endian variants of ioread/iowrite 2005-04-16 15:25:54 -07:00
ppc [PATCH] ppc user annotations: debug_setconetext(2) 2005-04-25 07:55:59 -07:00
ppc64 [PATCH] ppc64: Fix return value of some vDSO calls 2005-04-27 18:04:45 -07:00
s390 Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sh [PATCH] fix u32 vs. pm_message_t in rest of the tree 2005-04-16 15:25:37 -07:00
sh64 Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sparc [SPARC]: dump_stack for sparc 2005-04-24 20:46:49 -07:00
sparc64 [PATCH] mostek bogus sparse annotations fixed 2005-04-24 12:28:36 -07:00
um [PATCH] uml: fix compilation for __CHOOSE_MODE addition 2005-04-16 15:25:39 -07:00
v850 Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
x86_64 [PATCH] x86_64: fix PT_NOTE addition to IA32 vDSO 2005-04-28 22:47:29 -07:00