Commit 47fee31d authored Dec 22, 2017 by Nicholas Piggin Committed by Michael Ellerman Jan 18, 2018

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

Commit 177ba7c6 ("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>

parent 98ae0069

arch/powerpc/kernel/entry_64.S

+11 −6

Original line number	Diff line number	Diff line
		@@ -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 */