Le 12/01/2019 à 10:55, Christophe Leroy a écrit :
The purpose of this serie is to activate CONFIG_THREAD_INFO_IN_TASK which
moves the thread_info into task_struct.
Moving thread_info into task_struct has the following advantages:
- It protects thread_info from corruption in the case of stack
overflows.
- Its address is harder to determine if stack addresses are
leaked, making a number of attacks more difficult.
I ran null_syscall and context_switch benchmark selftests and the result
is surprising. There is slight degradation in context_switch and a
significant one on null_syscall:
Without the serie:
~# chrt -f 98 ./context_switch --no-altivec --no-vector --no-fp
55542
55562
55564
55562
55568
...
~# ./null_syscall
2546.71 ns 336.17 cycles
With the serie:
~# chrt -f 98 ./context_switch --no-altivec --no-vector --no-fp
55138
55142
55152
55144
55142
~# ./null_syscall
3479.54 ns 459.30 cycles
So 0,8% less context switches per second and 37% more time for one syscall ?
Any idea ?
Christophe
Changes since v12:
- Patch 1: Taken comment from Mike (re-introduced the 'panic' in case
memblock allocation fails in setup_64.c
- Patch 1: Added alloc_stack() function in setup_32.c to also panic in case
of allocation failure.
Changes since v11:
- Rebased on 81775f5563fa ("Automatic merge of branches 'master', 'next' and
'fixes' into merge")
- Added a first patch to change memblock allocs to functions returning
virtual addrs. This removes
the memset() which were the only remaining stuff in irq_ctx_init() and
exc_lvl_ctx_init() at the end.
- dropping irq_ctx_init() and exc_lvl_ctx_init() in patch 5 (powerpc:
Activate CONFIG_THREAD_INFO_IN_TASK)
- A few cosmetic changes in commit log and code.
Changes since v10:
- Rebased on 21622a0d2023 ("Automatic merge of branches 'master', 'next' and
'fixes' into merge")
==> Fixed conflict in setup_32.S
Changes since v9:
- Rebased on 183cbf93be88 ("Automatic merge of branches 'master', 'next' and
'fixes' into merge")
==> Fixed conflict on xmon
Changes since v8:
- Rebased on e589b79e40d9 ("Automatic merge of branches 'master', 'next' and
'fixes' into merge")
==> Main impact was conflicts due to commit 9a8dd708d547 ("memblock: rename
memblock_alloc{_nid,_try_nid} to memblock_phys_alloc*")
Changes since v7:
- Rebased on fb6c6ce7907d ("Automatic merge of branches 'master', 'next' and
'fixes' into merge")
Changes since v6:
- Fixed validate_sp() to exclude NULL sp in 'regain entire stack space' patch
(early crash with CONFIG_KMEMLEAK)
Changes since v5:
- Fixed livepatch_sp setup by using end_of_stack() instead of hardcoding
- Fixed PPC_BPF_LOAD_CPU() macro
Changes since v4:
- Fixed a build failure on 32bits SMP when include/generated/asm-offsets.h is
not
already existing, was due to spaces instead of a tab in the Makefile
Changes since RFC v3: (based on Nick's review)
- Renamed task_size.h to task_size_user64.h to better relate to what it
contains.
- Handling of the isolation of thread_info cpu field inside CONFIG_SMP
#ifdefs moved to a separate patch.
- Removed CURRENT_THREAD_INFO macro completely.
- Added a guard in asm/smp.h to avoid build failure before _TASK_CPU is
defined.
- Added a patch at the end to rename 'tp' pointers to 'sp' pointers
- Renamed 'tp' into 'sp' pointers in preparation patch when relevant
- Fixed a few commit logs
- Fixed checkpatch report.
Changes since RFC v2:
- Removed the modification of names in asm-offsets
- Created a rule in arch/powerpc/Makefile to append the offset of
current->cpu in CFLAGS
- Modified asm/smp.h to use the offset set in CFLAGS
- Squashed the renaming of THREAD_INFO to TASK_STACK in the preparation patch
- Moved the modification of current_pt_regs in the patch activating
CONFIG_THREAD_INFO_IN_TASK
Changes since RFC v1:
- Removed the first patch which was modifying header inclusion order in timer
- Modified some names in asm-offsets to avoid conflicts when including
asm-offsets in C files
- Modified asm/smp.h to avoid having to include linux/sched.h (using
asm-offsets instead)
- Moved some changes from the activation patch to the preparation patch.
Christophe Leroy (10):
powerpc/irq: use memblock functions returning virtual address
book3s/64: avoid circular header inclusion in mmu-hash.h
powerpc: Only use task_struct 'cpu' field on SMP
powerpc: Prepare for moving thread_info into task_struct
powerpc: Activate CONFIG_THREAD_INFO_IN_TASK
powerpc: regain entire stack space
powerpc: 'current_set' is now a table of task_struct pointers
powerpc/32: Remove CURRENT_THREAD_INFO and rename TI_CPU
powerpc/64: Remove CURRENT_THREAD_INFO
powerpc: clean stack pointers naming
arch/powerpc/Kconfig | 1 +
arch/powerpc/Makefile | 7 ++
arch/powerpc/include/asm/asm-prototypes.h | 4 +-
arch/powerpc/include/asm/book3s/64/mmu-hash.h | 2 +-
arch/powerpc/include/asm/exception-64s.h | 4 +-
arch/powerpc/include/asm/irq.h | 18 ++--
arch/powerpc/include/asm/livepatch.h | 6 +-
arch/powerpc/include/asm/processor.h | 39 +--------
arch/powerpc/include/asm/ptrace.h | 2 +-
arch/powerpc/include/asm/reg.h | 2 +-
arch/powerpc/include/asm/smp.h | 17 +++-
arch/powerpc/include/asm/task_size_user64.h | 42 +++++++++
arch/powerpc/include/asm/thread_info.h | 19 -----
arch/powerpc/kernel/asm-offsets.c | 10 ++-
arch/powerpc/kernel/entry_32.S | 66 +++++---------
arch/powerpc/kernel/entry_64.S | 12 +--
arch/powerpc/kernel/epapr_hcalls.S | 5 +-
arch/powerpc/kernel/exceptions-64e.S | 13 +--
arch/powerpc/kernel/exceptions-64s.S | 2 +-
arch/powerpc/kernel/head_32.S | 14 +--
arch/powerpc/kernel/head_40x.S | 4 +-
arch/powerpc/kernel/head_44x.S | 8 +-
arch/powerpc/kernel/head_64.S | 1 +
arch/powerpc/kernel/head_8xx.S | 2 +-
arch/powerpc/kernel/head_booke.h | 12 +--
arch/powerpc/kernel/head_fsl_booke.S | 16 ++--
arch/powerpc/kernel/idle_6xx.S | 8 +-
arch/powerpc/kernel/idle_book3e.S | 2 +-
arch/powerpc/kernel/idle_e500.S | 8 +-
arch/powerpc/kernel/idle_power4.S | 2 +-
arch/powerpc/kernel/irq.c | 114 +++----------------------
arch/powerpc/kernel/kgdb.c | 28 ------
arch/powerpc/kernel/machine_kexec_64.c | 6 +-
arch/powerpc/kernel/misc_32.S | 17 ++--
arch/powerpc/kernel/process.c | 40 ++++-----
arch/powerpc/kernel/setup-common.c | 2 +-
arch/powerpc/kernel/setup_32.c | 25 +++---
arch/powerpc/kernel/setup_64.c | 51 +++--------
arch/powerpc/kernel/smp.c | 16 ++--
arch/powerpc/kernel/trace/ftrace_64_mprofile.S | 6 +-
arch/powerpc/kvm/book3s_hv_hmi.c | 1 +
arch/powerpc/mm/hash_low_32.S | 14 ++-
arch/powerpc/net/bpf_jit32.h | 5 +-
arch/powerpc/sysdev/6xx-suspend.S | 5 +-
arch/powerpc/xmon/xmon.c | 2 +-
45 files changed, 249 insertions(+), 431 deletions(-)
create mode 100644 arch/powerpc/include/asm/task_size_user64.h
