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ce3dc44749
With virtually mapped kernel stacks the kernel stack overflow detection is now fault based, every stack has a guard page in the vmalloc space. The panic_stack is renamed to nodat_stack and is used for all function that need to run without DAT, e.g. memcpy_real or do_start_kdump. The main effect is a reduction in the kernel image size as with vmap stacks the old style overflow checking that adds two instructions per function is not needed anymore. Result from bloat-o-meter: add/remove: 20/1 grow/shrink: 13/26854 up/down: 2198/-216240 (-214042) In regard to performance the micro-benchmark for fork has a hit of a few microseconds, allocating 4 pages in vmalloc space is more expensive compare to an order-2 page allocation. But with real workload I could not find a noticeable difference. Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
100 lines
2.9 KiB
ArmAsm
100 lines
2.9 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright IBM Corp. 1999, 2010
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*
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* Author(s): Hartmut Penner <hp@de.ibm.com>
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* Martin Schwidefsky <schwidefsky@de.ibm.com>
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* Rob van der Heij <rvdhei@iae.nl>
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* Heiko Carstens <heiko.carstens@de.ibm.com>
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*
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*/
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#include <linux/init.h>
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#include <linux/linkage.h>
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#include <asm/asm-offsets.h>
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#include <asm/thread_info.h>
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#include <asm/page.h>
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#include <asm/ptrace.h>
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__HEAD
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ENTRY(startup_continue)
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tm __LC_STFLE_FAC_LIST+5,0x80 # LPP available ?
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jz 0f
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xc __LC_LPP+1(7,0),__LC_LPP+1 # clear lpp and current_pid
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mvi __LC_LPP,0x80 # and set LPP_MAGIC
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.insn s,0xb2800000,__LC_LPP # load program parameter
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0: larl %r1,tod_clock_base
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mvc 0(16,%r1),__LC_BOOT_CLOCK
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larl %r13,.LPG1 # get base
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lctlg %c0,%c15,.Lctl-.LPG1(%r13) # load control registers
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lg %r12,.Lparmaddr-.LPG1(%r13) # pointer to parameter area
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# move IPL device to lowcore
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larl %r0,boot_vdso_data
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stg %r0,__LC_VDSO_PER_CPU
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#
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# Setup stack
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#
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larl %r14,init_task
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stg %r14,__LC_CURRENT
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larl %r15,init_thread_union+THREAD_SIZE-STACK_FRAME_OVERHEAD
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#
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# Early setup functions that may not rely on an initialized bss section,
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# like moving the initrd. Returns with an initialized bss section.
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#
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brasl %r14,startup_init_nobss
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#
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# Early machine initialization and detection functions.
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#
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brasl %r14,startup_init
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# check control registers
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stctg %c0,%c15,0(%r15)
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oi 6(%r15),0x60 # enable sigp emergency & external call
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oi 4(%r15),0x10 # switch on low address proctection
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lctlg %c0,%c15,0(%r15)
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lam 0,15,.Laregs-.LPG1(%r13) # load acrs needed by uaccess
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brasl %r14,start_kernel # go to C code
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#
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# We returned from start_kernel ?!? PANIK
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#
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basr %r13,0
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lpswe .Ldw-.(%r13) # load disabled wait psw
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.align 16
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.LPG1:
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.Lctl: .quad 0x04040000 # cr0: AFP registers & secondary space
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.quad 0 # cr1: primary space segment table
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.quad .Lduct # cr2: dispatchable unit control table
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.quad 0 # cr3: instruction authorization
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.quad 0xffff # cr4: instruction authorization
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.quad .Lduct # cr5: primary-aste origin
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.quad 0 # cr6: I/O interrupts
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.quad 0 # cr7: secondary space segment table
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.quad 0 # cr8: access registers translation
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.quad 0 # cr9: tracing off
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.quad 0 # cr10: tracing off
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.quad 0 # cr11: tracing off
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.quad 0 # cr12: tracing off
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.quad 0 # cr13: home space segment table
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.quad 0xc0000000 # cr14: machine check handling off
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.quad .Llinkage_stack # cr15: linkage stack operations
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.Lpcmsk:.quad 0x0000000180000000
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.L4malign:.quad 0xffffffffffc00000
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.Lscan2g:.quad 0x80000000 + 0x20000 - 8 # 2GB + 128K - 8
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.Lnop: .long 0x07000700
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.Lparmaddr:
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.quad PARMAREA
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.align 64
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.Lduct: .long 0,.Laste,.Laste,0,.Lduald,0,0,0
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.long 0,0,0,0,0,0,0,0
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.Laste: .quad 0,0xffffffffffffffff,0,0,0,0,0,0
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.align 128
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.Lduald:.rept 8
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.long 0x80000000,0,0,0 # invalid access-list entries
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.endr
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.Llinkage_stack:
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.long 0,0,0x89000000,0,0,0,0x8a000000,0
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.Ldw: .quad 0x0002000180000000,0x0000000000000000
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.Laregs:.long 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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