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| author | Zeng Chi <zengchi@kylinos.cn> | 2026-09-21 18:24:42 +0800 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2026-09-22 08:36:16 -0700 |
| commit | 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d (patch) | |
| tree | 660d50d4139cb750fbde1ae3432452c20726c99d /arch/mips/lib/uncached.c | |
| download | linux-stable-119e9db233ad0f4cbd4cfb9f9385a7bca378b37d.tar.gz linux-stable-119e9db233ad0f4cbd4cfb9f9385a7bca378b37d.zip | |
KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted
Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.
Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/mips/lib/uncached.c')
| -rw-r--r-- | arch/mips/lib/uncached.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/arch/mips/lib/uncached.c b/arch/mips/lib/uncached.c new file mode 100644 index 000000000..f80a67c09 --- /dev/null +++ b/arch/mips/lib/uncached.c @@ -0,0 +1,82 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2005 Thiemo Seufer + * Copyright (C) 2005 MIPS Technologies, Inc. All rights reserved. + * Author: Maciej W. Rozycki <macro@mips.com> + */ + + +#include <asm/addrspace.h> +#include <asm/bug.h> +#include <asm/cacheflush.h> + +#ifndef CKSEG2 +#define CKSEG2 CKSSEG +#endif +#ifndef TO_PHYS_MASK +#define TO_PHYS_MASK -1 +#endif + +/* + * FUNC is executed in one of the uncached segments, depending on its + * original address as follows: + * + * 1. If the original address is in CKSEG0 or CKSEG1, then the uncached + * segment used is CKSEG1. + * 2. If the original address is in XKPHYS, then the uncached segment + * used is XKPHYS(2). + * 3. Otherwise it's a bug. + * + * The same remapping is done with the stack pointer. Stack handling + * works because we don't handle stack arguments or more complex return + * values, so we can avoid sharing the same stack area between a cached + * and the uncached mode. + */ +unsigned long run_uncached(void *func) +{ + register long ret __asm__("$2"); + long lfunc = (long)func, ufunc; + long usp; + long sp; + + __asm__("move %0, $sp" : "=r" (sp)); + + if (sp >= (long)CKSEG0 && sp < (long)CKSEG2) + usp = CKSEG1ADDR(sp); +#ifdef CONFIG_64BIT + else if ((long long)sp >= (long long)PHYS_TO_XKPHYS(0, 0) && + (long long)sp < (long long)PHYS_TO_XKPHYS(8, 0)) + usp = PHYS_TO_XKPHYS(K_CALG_UNCACHED, + XKPHYS_TO_PHYS((long long)sp)); +#endif + else { + BUG(); + usp = sp; + } + if (lfunc >= (long)CKSEG0 && lfunc < (long)CKSEG2) + ufunc = CKSEG1ADDR(lfunc); +#ifdef CONFIG_64BIT + else if ((long long)lfunc >= (long long)PHYS_TO_XKPHYS(0, 0) && + (long long)lfunc < (long long)PHYS_TO_XKPHYS(8, 0)) + ufunc = PHYS_TO_XKPHYS(K_CALG_UNCACHED, + XKPHYS_TO_PHYS((long long)lfunc)); +#endif + else { + BUG(); + ufunc = lfunc; + } + + __asm__ __volatile__ ( + " move $16, $sp\n" + " move $sp, %1\n" + " jalr %2\n" + " move $sp, $16" + : "=r" (ret) + : "r" (usp), "r" (ufunc) + : "$16", "$31"); + + return ret; +} |