From: Huacai Chen chenhuacai@loongson.cn
commit dce5ea1d0f45fa612f5760b88614a3f32bc75e3f upstream.
vm_map_base, empty_zero_page and invalid_pmd_table could be accessed widely by some out-of-tree non-GPL but important file systems or drivers (e.g. OpenZFS). Let's use EXPORT_SYMBOL() instead of EXPORT_SYMBOL_GPL() to export them, so as to avoid build errors.
1, Details about vm_map_base:
This is a LoongArch-specific symbol and may be referenced through macros PCI_IOBASE, VMALLOC_START and VMALLOC_END.
2, Details about empty_zero_page:
As it stands today, only 3 architectures export empty_zero_page as a GPL symbol: IA64, LoongArch and MIPS. LoongArch gets the GPL export by inheriting from MIPS, and the MIPS export was first introduced in commit 497d2adcbf50b ("[MIPS] Export empty_zero_page for sake of the ext4 module."). The IA64 export was similar: commit a7d57ecf4216e ("[IA64] Export three symbols for module use") did so for kvm.
In both IA64 and MIPS, the export of empty_zero_page was done for satisfying some in-kernel component built as module (kvm and ext4 respectively), and given its reasonably low-level nature, GPL is a reasonable choice. But looking at the bigger picture it is evident most other architectures do not regard it as GPL, so in effect the symbol probably should not be treated as such, in favor of consistency.
3, Details about invalid_pmd_table:
Keep consistency with invalid_pte_table and make it be possible by some modules.
Cc: stable@vger.kernel.org Reviewed-by: WANG Xuerui git@xen0n.name Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/loongarch/kernel/cpu-probe.c | 2 +- arch/loongarch/mm/init.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)
--- a/arch/loongarch/kernel/cpu-probe.c +++ b/arch/loongarch/kernel/cpu-probe.c @@ -60,7 +60,7 @@ static inline void set_elf_platform(int
/* MAP BASE */ unsigned long vm_map_base; -EXPORT_SYMBOL_GPL(vm_map_base); +EXPORT_SYMBOL(vm_map_base);
static void cpu_probe_addrbits(struct cpuinfo_loongarch *c) { --- a/arch/loongarch/mm/init.c +++ b/arch/loongarch/mm/init.c @@ -41,7 +41,7 @@ * don't have to care about aliases on other CPUs. */ unsigned long empty_zero_page, zero_page_mask; -EXPORT_SYMBOL_GPL(empty_zero_page); +EXPORT_SYMBOL(empty_zero_page); EXPORT_SYMBOL(zero_page_mask);
void setup_zero_pages(void) @@ -270,7 +270,7 @@ pud_t invalid_pud_table[PTRS_PER_PUD] __ #endif #ifndef __PAGETABLE_PMD_FOLDED pmd_t invalid_pmd_table[PTRS_PER_PMD] __page_aligned_bss; -EXPORT_SYMBOL_GPL(invalid_pmd_table); +EXPORT_SYMBOL(invalid_pmd_table); #endif pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned_bss; EXPORT_SYMBOL(invalid_pte_table);