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| author | Alexander Graf <agraf@suse.de> | 2016-03-04 01:09:47 +0100 |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2016-03-15 15:13:01 -0400 |
| commit | 5e2ec773bb6c5acf22d8652112856e87cff86ea4 (patch) | |
| tree | ae75a1cab47d1d59c91ccc5a5d2579c64dab47a1 /arch/arm/cpu/armv8/cache.S | |
| parent | 9bb367a590feac21d674e4d2cee77702d4774819 (diff) | |
| download | u-boot-imx-5e2ec773bb6c5acf22d8652112856e87cff86ea4.zip u-boot-imx-5e2ec773bb6c5acf22d8652112856e87cff86ea4.tar.gz u-boot-imx-5e2ec773bb6c5acf22d8652112856e87cff86ea4.tar.bz2 | |
arm64: Make full va map code more dynamic
The idea to generate our pages tables from an array of memory ranges
is very sound. However, instead of hard coding the code to create up
to 2 levels of 64k granule page tables, we really should just create
normal 4k page tables that allow us to set caching attributes on 2M
or 4k level later on.
So this patch moves the full_va mapping code to 4k page size and
makes it fully flexible to dynamically create as many levels as
necessary for a map (including dynamic 1G/2M pages). It also adds
support to dynamically split a large map into smaller ones when
some code wants to set dcache attributes.
With all this in place, there is very little reason to create your
own page tables in board specific files.
Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'arch/arm/cpu/armv8/cache.S')
| -rw-r--r-- | arch/arm/cpu/armv8/cache.S | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv8/cache.S b/arch/arm/cpu/armv8/cache.S index ab8c089..a9f4fec 100644 --- a/arch/arm/cpu/armv8/cache.S +++ b/arch/arm/cpu/armv8/cache.S @@ -10,6 +10,7 @@ #include <asm-offsets.h> #include <config.h> #include <asm/macro.h> +#include <asm/system.h> #include <linux/linkage.h> /* @@ -160,3 +161,56 @@ ENTRY(__asm_flush_l3_cache) ret ENDPROC(__asm_flush_l3_cache) .weak __asm_flush_l3_cache + +/* + * void __asm_switch_ttbr(ulong new_ttbr) + * + * Safely switches to a new page table. + */ +ENTRY(__asm_switch_ttbr) + /* x2 = SCTLR (alive throghout the function) */ + switch_el x4, 3f, 2f, 1f +3: mrs x2, sctlr_el3 + b 0f +2: mrs x2, sctlr_el2 + b 0f +1: mrs x2, sctlr_el1 +0: + + /* Unset CR_M | CR_C | CR_I from SCTLR to disable all caches */ + movn x1, #(CR_M | CR_C | CR_I) + and x1, x2, x1 + switch_el x4, 3f, 2f, 1f +3: msr sctlr_el3, x1 + b 0f +2: msr sctlr_el2, x1 + b 0f +1: msr sctlr_el1, x1 +0: isb + + /* This call only clobbers x30 (lr) and x9 (unused) */ + mov x3, x30 + bl __asm_invalidate_tlb_all + + /* From here on we're running safely with caches disabled */ + + /* Set TTBR to our first argument */ + switch_el x4, 3f, 2f, 1f +3: msr ttbr0_el3, x0 + b 0f +2: msr ttbr0_el2, x0 + b 0f +1: msr ttbr0_el1, x0 +0: isb + + /* Restore original SCTLR and thus enable caches again */ + switch_el x4, 3f, 2f, 1f +3: msr sctlr_el3, x2 + b 0f +2: msr sctlr_el2, x2 + b 0f +1: msr sctlr_el1, x2 +0: isb + + ret x3 +ENDPROC(__asm_switch_ttbr) |