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powerpc/64: rtas avoid accessing paca in 32-bit mode

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Commit 177ba7c647 ("powerpc/mm/radix: Limit paca allocation in radix")
limited the paca allocation address to 1G on pSeries because RTAS return
accesses the paca in 32-bit mode:

    On return from RTAS we access the paca variables and we have 64 bit
    disabled. This requires us to limit paca in 32 bit range.

    Fix this by setting ppc64_rma_size to first_memblock_size/1G range.

Avoid this limit by switching to 64-bit mode before accessing any memory.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2017-12-22 21:17:10 +10:00 committed by Michael Ellerman
parent 98ae0069cb
commit 47fee31dbd
1 changed files with 11 additions and 6 deletions
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17
arch/powerpc/kernel/entry_64.S
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@ -1083,6 +1083,17 @@ __enter_rtas:
rtas_return_loc:
FIXUP_ENDIAN
/*
* Clear RI and set SF before anything.
*/
mfmsr r6
li r0,MSR_RI
andc r6,r6,r0
sldi r0,r0,(MSR_SF_LG - MSR_RI_LG)
or r6,r6,r0
sync
mtmsrd r6
/* relocation is off at this point */
GET_PACA(r4)
clrldi r4,r4,2 /* convert to realmode address */
@ -1091,12 +1102,6 @@ rtas_return_loc:
0: mflr r3
ld r3,(1f-0b)(r3) /* get &rtas_restore_regs */
mfmsr r6
li r0,MSR_RI
andc r6,r6,r0
sync
mtmsrd r6
ld r1,PACAR1(r4) /* Restore our SP */
ld r4,PACASAVEDMSR(r4) /* Restore our MSR */