Hi Paul,

On Thu, Aug 30, 2018 at 02:48:57PM -0700, Paul Burton wrote:

Hi Mike,

On Mon, Aug 27, 2018 at 10:59:35AM +0300, Mike Rapoport wrote:

quoted

MIPS already has memblock support and all the memory is already registered
with it.

This patch replaces bootmem memory reservations with memblock ones and
removes the bootmem initialization.

Signed-off-by: Mike Rapoport <redacted>
---

 arch/mips/Kconfig                      |  1 +
 arch/mips/kernel/setup.c               | 89 +++++-----------------------------
 arch/mips/loongson64/loongson-3/numa.c | 34 ++++++-------
 arch/mips/sgi-ip27/ip27-memory.c       | 11 ++---
 4 files changed, 33 insertions(+), 102 deletions(-)

Thanks for working on this. Unfortunately it breaks boot for at least a
32r6el_defconfig kernel on QEMU:

  $ qemu-system-mips64el \
    -M boston \
    -kernel arch/mips/boot/vmlinux.gz.itb \
    -serial stdio \
    -append "earlycon=uart8250,mmio32,0x17ffe000,115200 console=ttyS0,115200 debug memblock=debug mminit_loglevel=4"
  [    0.000000] Linux version 4.19.0-rc1-00008-g82d0f342eecd (pburton@pburton-laptop) (gcc version 8.1.0 (GCC)) #23 SMP Thu Aug 30 14:38:06 PDT 2018
  [    0.000000] CPU0 revision is: 0001a900 (MIPS I6400)
  [    0.000000] FPU revision is: 20f30300
  [    0.000000] MSA revision is: 00000300
  [    0.000000] MIPS: machine is img,boston
  [    0.000000] Determined physical RAM map:
  [    0.000000]  memory: 10000000 @ 00000000 (usable)
  [    0.000000]  memory: 30000000 @ 90000000 (usable)
  [    0.000000] earlycon: uart8250 at MMIO32 0x17ffe000 (options '115200')
  [    0.000000] bootconsole [uart8250] enabled
  [    0.000000] memblock_reserve: [0x00000000-0x009a8fff] setup_arch+0x224/0x718
  [    0.000000] memblock_reserve: [0x01360000-0x01361ca7] setup_arch+0x3d8/0x718
  [    0.000000] Initrd not found or empty - disabling initrd
  [    0.000000] memblock_virt_alloc_try_nid: 7336 bytes align=0x40 nid=-1 from=0x00000000 max_addr=0x00000000 early_init_dt_alloc_memory_arch+0x20/0x2c
  [    0.000000] memblock_reserve: [0xbfffe340-0xbfffffe7] memblock_virt_alloc_internal+0x120/0x1ec
  <hang>

It looks like we took a TLB store exception after calling memset() with
a bogus address from memblock_virt_alloc_try_nid() or something inlined
into it.

Memblock tries to allocate from the top and the resulting address ends up
in the high memory. 

With the hunk below I was able to get to "VFS: Cannot open root device"

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 4114d3c..4a9b0f7 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c

@@ -577,6 +577,8 @@ static void __init bootmem_init(void)
         * Reserve initrd memory if needed.
         */
        finalize_initrd();
+
+       memblock_set_bottom_up(true);
 }
 
 #endif /* CONFIG_SGI_IP27 */
 

This was with your patch applied atop the mips-next branch from [1],
which is currently at commit 35d017947401 ("MIPS: ralink: Add rt3352
SPI_CS1 pinmux").

Thanks,
    Paul

[1] git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux.git

-- 
Sincerely yours,
Mike.