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arm64: mmu: Make __cpu_replace_ttbr1() out of line

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__cpu_replace_ttbr1() is a static inline, and so it gets instantiated
wherever it is used. This is not really necessary, as it is never called
on a hot path. It also has the unfortunate side effect that the symbol
idmap_cpu_replace_ttbr1 may never be referenced from kCFI enabled C
code, and this means the type id symbol may not exist either.  This will
result in a build error once we start referring to this symbol from asm
code as well. (Note that this problem only occurs when CnP, KAsan and
suspend/resume are all disabled in the Kconfig but that is a valid
config, if unusual).

So let's just move it out of line so all callers will share the same
implementation, which will reference idmap_cpu_replace_ttbr1
unconditionally.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-62-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Ard Biesheuvel
2024-02-14 13:29:03 +01:00
committed by Catalin Marinas
parent 293d865f0a
commit 82ca151da7
2 changed files with 33 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
arch/arm64/include/asm/mmu_context.h
View File

@@ -148,37 +148,7 @@ static inline void cpu_install_ttbr0(phys_addr_t ttbr0, unsigned long t0sz)
isb();
}
/*
* Atomically replaces the active TTBR1_EL1 PGD with a new VA-compatible PGD,
* avoiding the possibility of conflicting TLB entries being allocated.
*/
static inline void __cpu_replace_ttbr1(pgd_t *pgdp, pgd_t *idmap, bool cnp)
{
typedef void (ttbr_replace_func)(phys_addr_t);
extern ttbr_replace_func idmap_cpu_replace_ttbr1;
ttbr_replace_func *replace_phys;
unsigned long daif;
/* phys_to_ttbr() zeros lower 2 bits of ttbr with 52-bit PA */
phys_addr_t ttbr1 = phys_to_ttbr(virt_to_phys(pgdp));
if (cnp)
ttbr1 |= TTBR_CNP_BIT;
replace_phys = (void *)__pa_symbol(idmap_cpu_replace_ttbr1);
__cpu_install_idmap(idmap);
/*
* We really don't want to take *any* exceptions while TTBR1 is
* in the process of being replaced so mask everything.
*/
daif = local_daif_save();
replace_phys(ttbr1);
local_daif_restore(daif);
cpu_uninstall_idmap();
}
void __cpu_replace_ttbr1(pgd_t *pgdp, pgd_t *idmap, bool cnp);
static inline void cpu_enable_swapper_cnp(void)
{

32
arch/arm64/mm/mmu.c
View File

@@ -1486,3 +1486,35 @@ void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, pte
{
set_pte_at(vma->vm_mm, addr, ptep, pte);
}
/*
* Atomically replaces the active TTBR1_EL1 PGD with a new VA-compatible PGD,
* avoiding the possibility of conflicting TLB entries being allocated.
*/
void __cpu_replace_ttbr1(pgd_t *pgdp, pgd_t *idmap, bool cnp)
{
typedef void (ttbr_replace_func)(phys_addr_t);
extern ttbr_replace_func idmap_cpu_replace_ttbr1;
ttbr_replace_func *replace_phys;
unsigned long daif;
/* phys_to_ttbr() zeros lower 2 bits of ttbr with 52-bit PA */
phys_addr_t ttbr1 = phys_to_ttbr(virt_to_phys(pgdp));
if (cnp)
ttbr1 |= TTBR_CNP_BIT;
replace_phys = (void *)__pa_symbol(idmap_cpu_replace_ttbr1);
__cpu_install_idmap(idmap);
/*
* We really don't want to take *any* exceptions while TTBR1 is
* in the process of being replaced so mask everything.
*/
daif = local_daif_save();
replace_phys(ttbr1);
local_daif_restore(daif);
cpu_uninstall_idmap();
}