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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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b2d4383480
Choose PAGE_OFFSET dynamically based upon cpu type. Original UltraSPARC-I (spitfire) chips only supported a 44-bit virtual address space. Newer chips (T4 and later) support 52-bit virtual addresses and up to 47-bits of physical memory space. Therefore we have to adjust PAGE_SIZE dynamically based upon the capabilities of the chip. Note that this change alone does not allow us to support > 43-bit physical memory, to do that we need to re-arrange our page table support. The current encodings of the pmd_t and pgd_t pointers restricts us to "32 + 11" == 43 bits. This change can waste quite a bit of memory for the various tables. In particular, a future change should work to size and allocate kern_linear_bitmap[] and sparc64_valid_addr_bitmap[] dynamically. This isn't easy as we really cannot take a TLB miss when accessing kern_linear_bitmap[]. We'd have to lock it into the TLB or similar. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Bob Picco <bob.picco@oracle.com>
104 lines
2.4 KiB
ArmAsm
104 lines
2.4 KiB
ArmAsm
/* clear_page.S: UltraSparc optimized clear page.
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*
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* Copyright (C) 1996, 1998, 1999, 2000, 2004 David S. Miller (davem@redhat.com)
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* Copyright (C) 1997 Jakub Jelinek (jakub@redhat.com)
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*/
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#include <asm/visasm.h>
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#include <asm/thread_info.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/spitfire.h>
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#include <asm/head.h>
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/* What we used to do was lock a TLB entry into a specific
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* TLB slot, clear the page with interrupts disabled, then
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* restore the original TLB entry. This was great for
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* disturbing the TLB as little as possible, but it meant
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* we had to keep interrupts disabled for a long time.
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*
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* Now, we simply use the normal TLB loading mechanism,
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* and this makes the cpu choose a slot all by itself.
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* Then we do a normal TLB flush on exit. We need only
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* disable preemption during the clear.
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*/
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.text
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.globl _clear_page
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_clear_page: /* %o0=dest */
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ba,pt %xcc, clear_page_common
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clr %o4
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/* This thing is pretty important, it shows up
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* on the profiles via do_anonymous_page().
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*/
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.align 32
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.globl clear_user_page
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clear_user_page: /* %o0=dest, %o1=vaddr */
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lduw [%g6 + TI_PRE_COUNT], %o2
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sethi %hi(PAGE_OFFSET), %g2
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sethi %hi(PAGE_SIZE), %o4
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ldx [%g2 + %lo(PAGE_OFFSET)], %g2
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sethi %hi(PAGE_KERNEL_LOCKED), %g3
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ldx [%g3 + %lo(PAGE_KERNEL_LOCKED)], %g3
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sub %o0, %g2, %g1 ! paddr
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and %o1, %o4, %o0 ! vaddr D-cache alias bit
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or %g1, %g3, %g1 ! TTE data
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sethi %hi(TLBTEMP_BASE), %o3
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add %o2, 1, %o4
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add %o0, %o3, %o0 ! TTE vaddr
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/* Disable preemption. */
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mov TLB_TAG_ACCESS, %g3
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stw %o4, [%g6 + TI_PRE_COUNT]
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/* Load TLB entry. */
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rdpr %pstate, %o4
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wrpr %o4, PSTATE_IE, %pstate
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stxa %o0, [%g3] ASI_DMMU
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stxa %g1, [%g0] ASI_DTLB_DATA_IN
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sethi %hi(KERNBASE), %g1
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flush %g1
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wrpr %o4, 0x0, %pstate
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mov 1, %o4
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clear_page_common:
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VISEntryHalf
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membar #StoreLoad | #StoreStore | #LoadStore
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fzero %f0
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sethi %hi(PAGE_SIZE/64), %o1
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mov %o0, %g1 ! remember vaddr for tlbflush
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fzero %f2
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or %o1, %lo(PAGE_SIZE/64), %o1
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faddd %f0, %f2, %f4
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fmuld %f0, %f2, %f6
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faddd %f0, %f2, %f8
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fmuld %f0, %f2, %f10
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faddd %f0, %f2, %f12
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fmuld %f0, %f2, %f14
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1: stda %f0, [%o0 + %g0] ASI_BLK_P
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subcc %o1, 1, %o1
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bne,pt %icc, 1b
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add %o0, 0x40, %o0
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membar #Sync
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VISExitHalf
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brz,pn %o4, out
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nop
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stxa %g0, [%g1] ASI_DMMU_DEMAP
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membar #Sync
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stw %o2, [%g6 + TI_PRE_COUNT]
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out: retl
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nop
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