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    Subject[PATCH 5.16 0758/1039] powerpc/40x: Map 32Mbytes of memory at startup
    Date
    From: Christophe Leroy <christophe.leroy@csgroup.eu>

    [ Upstream commit 06e7cbc29e97b4713b4ea6def04ae8501a7d1a59 ]

    As reported by Carlo, 16Mbytes is not enough with modern kernels
    that tend to be a bit big, so map another 16M page at boot.

    Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
    Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
    Link: https://lore.kernel.org/r/89b5f974a7fa5011206682cd092e2c905530ff46.1632755552.git.christophe.leroy@csgroup.eu
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/powerpc/kernel/head_40x.S | 9 ++++++++-
    1 file changed, 8 insertions(+), 1 deletion(-)

    diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
    index 7d72ee5ab387c..e783860bea838 100644
    --- a/arch/powerpc/kernel/head_40x.S
    +++ b/arch/powerpc/kernel/head_40x.S
    @@ -27,6 +27,7 @@

    #include <linux/init.h>
    #include <linux/pgtable.h>
    +#include <linux/sizes.h>
    #include <asm/processor.h>
    #include <asm/page.h>
    #include <asm/mmu.h>
    @@ -650,7 +651,7 @@ start_here:
    b . /* prevent prefetch past rfi */

    /* Set up the initial MMU state so we can do the first level of
    - * kernel initialization. This maps the first 16 MBytes of memory 1:1
    + * kernel initialization. This maps the first 32 MBytes of memory 1:1
    * virtual to physical and more importantly sets the cache mode.
    */
    initial_mmu:
    @@ -687,6 +688,12 @@ initial_mmu:
    tlbwe r4,r0,TLB_DATA /* Load the data portion of the entry */
    tlbwe r3,r0,TLB_TAG /* Load the tag portion of the entry */

    + li r0,62 /* TLB slot 62 */
    + addis r4,r4,SZ_16M@h
    + addis r3,r3,SZ_16M@h
    + tlbwe r4,r0,TLB_DATA /* Load the data portion of the entry */
    + tlbwe r3,r0,TLB_TAG /* Load the tag portion of the entry */
    +
    isync

    /* Establish the exception vector base
    --
    2.34.1


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