[PATCH] RISC-V: Always compile mm/init.c with cmodel=medany

From: Anup Patel
Date: Sun Mar 24 2019 - 07:08:55 EST


The Linux RISC-V 32bit kernel is broken after we moved setup_vm() from
kernel/setup.c to mm/init.c because Linux RISC-V 32bit kernel by default
uses cmodel=medlow which results in a non-position-independent setup_vm().

This patch fixes Linux RISC-V 32bit kernel booting by:
1. Forcing cmodel=medany for mm/init.c
2. Moving remaing MM-related stuff va_pa_offset, pfn_base and
empty_zero_page from kernel/setup.c to mm/init.c

Fixes: 6f1e9e946f0b ("RISC-V: Move setup_vm() to mm/init.c")
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Signed-off-by: Anup Patel <anup.patel@xxxxxxx>
---
arch/riscv/kernel/setup.c | 8 --------
arch/riscv/mm/Makefile | 2 ++
arch/riscv/mm/init.c | 9 +++++++++
3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index ecb654f6a79e..540a331d1376 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -48,14 +48,6 @@ struct screen_info screen_info = {
};
#endif

-unsigned long va_pa_offset;
-EXPORT_SYMBOL(va_pa_offset);
-unsigned long pfn_base;
-EXPORT_SYMBOL(pfn_base);
-
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
/* The lucky hart to first increment this variable will boot the other cores */
atomic_t hart_lottery;
unsigned long boot_cpu_hartid;
diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile
index eb22ab49b3e0..7307609d405b 100644
--- a/arch/riscv/mm/Makefile
+++ b/arch/riscv/mm/Makefile
@@ -3,3 +3,5 @@ obj-y += fault.o
obj-y += extable.o
obj-y += ioremap.o
obj-y += cacheflush.o
+
+CFLAGS_init.o := -mcmodel=medany
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index b379a75ac6a6..1e7a106fb583 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -25,6 +25,15 @@
#include <asm/pgtable.h>
#include <asm/io.h>

+unsigned long va_pa_offset;
+EXPORT_SYMBOL(va_pa_offset);
+unsigned long pfn_base;
+EXPORT_SYMBOL(pfn_base);
+
+unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
+ __page_aligned_bss;
+EXPORT_SYMBOL(empty_zero_page);
+
static void __init zone_sizes_init(void)
{
unsigned long max_zone_pfns[MAX_NR_ZONES] = { 0, };
--
2.17.1