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authorHuang Pei <huangpei@loongson.cn>2021-03-13 04:39:27 +0300
committerThomas Bogendoerfer <tsbogend@alpha.franken.de>2021-03-14 16:08:15 +0300
commitc6972fb9ba8aab384568665411015b7deb8a8609 (patch)
tree6c28cfd26d67e3e5f9b12368e7dad65b0702a8b7 /arch/mips/Kconfig
parentc5a210453cf5c9140947533168077f518a01b4cd (diff)
downloadlinux-c6972fb9ba8aab384568665411015b7deb8a8609.tar.xz
MIPS: clean up CONFIG_MIPS_PGD_C0_CONTEXT handling
+. LOONGSON64 use 0x98xx_xxxx_xxxx_xxxx as xphys cached, instread of 0xa8xx_xxxx_xxxx_xxxx +. let CONFIG_MIPS_PGD_C0_CONTEXT depend on 64bit +. cast CAC_BASE into u64 to silence warning on MIPS32 CP0 Context has enough room for wraping pgd into its 41-bit PTEBase field. +. For XPHYS, the trick is that pgd is 4kB aligned, and the PABITS <= 53, only save 53 - 12 = 41 bits, aka : bit[63:59] | 0000 00 | bit[53:12] | 0000 0000 0000 +. for CKSEG0, only save 29 - 12 = 17 bits when switching pgd, only need to save bit[53:12] or bit[28:12] into CP0 Context's bit[63:23], see folling asm generated at run time tlbmiss_handler_setup_pgd: .set push .set noreorder dsra a2, a0, 29 move a3, a0 dins a0, zero, 29, 35 daddiu a2, a2, 4 //for CKSEG0, a2 from 0xfffffffffffffffc //into 0 movn a0, a3, a2 dsll a0, a0, 11 jr ra dmtc0 a0, CP0_CONTEXT .set pop when using it on page walking dmfc0 k0, CP0_CONTEXT dins k0, zero, 0, 23 // zero badv2 ori k0, k0, (CAC_BASE >> 53) // *prefix* with bit[63:59] drotr k0, k0, 11 // kick it in the right place Signed-off-by: Huang Pei <huangpei@loongson.cn> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Diffstat (limited to 'arch/mips/Kconfig')
-rw-r--r--arch/mips/Kconfig3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index b9ae8e7d95e0..160b3a890840 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2188,7 +2188,8 @@ config CPU_SUPPORTS_HUGEPAGES
depends on !(32BIT && (ARCH_PHYS_ADDR_T_64BIT || EVA))
config MIPS_PGD_C0_CONTEXT
bool
- default y if 64BIT && (CPU_MIPSR2 || CPU_MIPSR6) && !CPU_XLP
+ depends on 64BIT
+ default y if (CPU_MIPSR2 || CPU_MIPSR6) && !CPU_XLP
#
# Set to y for ptrace access to watch registers.