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b99afae139
The naked attribute is known to confuse some old gcc versions when
function arguments aren't explicitly listed as inline assembly operands
despite the gcc documentation. That resulted in commit 9a40ac8615
("ARM: 6164/1: Add kto and kfrom to input operands list.").
Yet that commit has problems of its own by having assembly operand
constraints completely wrong. If the generated code has been OK since
then, it is due to luck rather than correctness. So this patch also
provides proper assembly operand constraints, and removes two instances
of redundant register usages in the implementation while at it.
Inspection of the generated code with this patch doesn't show any
obvious quality degradation either, so not relying on __naked at all
will make the code less fragile, and avoid some issues with clang.
The only remaining __naked instances (excluding the kprobes test cases)
are exynos_pm_power_up_setup(), tc2_pm_power_up_setup() and
cci_enable_port_for_self(. But in the first two cases, only the function
address is used by the compiler with no chance of inlining it by
mistake, and the third case is called from assembly code only. And the
fact that no stack is available when the corresponding code is executed
does warrant the __naked usage in those cases.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Tested-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
106 lines
2.6 KiB
C
106 lines
2.6 KiB
C
/*
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* linux/arch/arm/mm/copypage-xsc3.S
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*
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* Copyright (C) 2004 Intel Corp.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Adapted for 3rd gen XScale core, no more mini-dcache
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* Author: Matt Gilbert (matthew.m.gilbert@intel.com)
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*/
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#include <linux/init.h>
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#include <linux/highmem.h>
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/*
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* General note:
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* We don't really want write-allocate cache behaviour for these functions
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* since that will just eat through 8K of the cache.
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*/
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/*
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* XSC3 optimised copy_user_highpage
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*
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* The source page may have some clean entries in the cache already, but we
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* can safely ignore them - break_cow() will flush them out of the cache
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* if we eventually end up using our copied page.
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*
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*/
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static void xsc3_mc_copy_user_page(void *kto, const void *kfrom)
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{
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int tmp;
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asm volatile ("\
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pld [%1, #0] \n\
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pld [%1, #32] \n\
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1: pld [%1, #64] \n\
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pld [%1, #96] \n\
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\n\
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2: ldrd r2, [%1], #8 \n\
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ldrd r4, [%1], #8 \n\
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mcr p15, 0, %0, c7, c6, 1 @ invalidate\n\
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strd r2, [%0], #8 \n\
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ldrd r2, [%1], #8 \n\
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strd r4, [%0], #8 \n\
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ldrd r4, [%1], #8 \n\
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strd r2, [%0], #8 \n\
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strd r4, [%0], #8 \n\
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ldrd r2, [%1], #8 \n\
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ldrd r4, [%1], #8 \n\
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mcr p15, 0, %0, c7, c6, 1 @ invalidate\n\
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strd r2, [%0], #8 \n\
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ldrd r2, [%1], #8 \n\
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subs %2, %2, #1 \n\
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strd r4, [%0], #8 \n\
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ldrd r4, [%1], #8 \n\
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strd r2, [%0], #8 \n\
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strd r4, [%0], #8 \n\
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bgt 1b \n\
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beq 2b "
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: "+&r" (kto), "+&r" (kfrom), "=&r" (tmp)
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: "2" (PAGE_SIZE / 64 - 1)
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: "r2", "r3", "r4", "r5");
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}
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void xsc3_mc_copy_user_highpage(struct page *to, struct page *from,
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unsigned long vaddr, struct vm_area_struct *vma)
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{
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void *kto, *kfrom;
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kto = kmap_atomic(to);
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kfrom = kmap_atomic(from);
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flush_cache_page(vma, vaddr, page_to_pfn(from));
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xsc3_mc_copy_user_page(kto, kfrom);
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kunmap_atomic(kfrom);
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kunmap_atomic(kto);
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}
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/*
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* XScale optimised clear_user_page
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*/
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void xsc3_mc_clear_user_highpage(struct page *page, unsigned long vaddr)
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{
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void *ptr, *kaddr = kmap_atomic(page);
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asm volatile ("\
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mov r1, %2 \n\
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mov r2, #0 \n\
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mov r3, #0 \n\
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1: mcr p15, 0, %0, c7, c6, 1 @ invalidate line\n\
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strd r2, [%0], #8 \n\
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strd r2, [%0], #8 \n\
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strd r2, [%0], #8 \n\
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strd r2, [%0], #8 \n\
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subs r1, r1, #1 \n\
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bne 1b"
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: "=r" (ptr)
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: "0" (kaddr), "I" (PAGE_SIZE / 32)
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: "r1", "r2", "r3");
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kunmap_atomic(kaddr);
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}
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struct cpu_user_fns xsc3_mc_user_fns __initdata = {
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.cpu_clear_user_highpage = xsc3_mc_clear_user_highpage,
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.cpu_copy_user_highpage = xsc3_mc_copy_user_highpage,
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};
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