Commit 68234df4 authored by Mark Rutland's avatar Mark Rutland Committed by Catalin Marinas
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arm64: kill flush_cache_all()

The documented semantics of flush_cache_all are not possible to provide
for arm64 (short of flushing the entire physical address space by VA),
and there are currently no users; KVM uses VA maintenance exclusively,
cpu_reset is never called, and the only two users outside of arch code
cannot be built for arm64.

While cpu_soft_reset and related functions (which call flush_cache_all)
were thought to be useful for kexec, their current implementations only
serve to mask bugs. For correctness kexec will need to perform
maintenance by VA anyway to account for system caches, line migration,
and other subtleties of the cache architecture. As the extent of this
cache maintenance will be kexec-specific, it should probably live in the
kexec code.

This patch removes flush_cache_all, and related unused components,
preventing further abuse.
Signed-off-by: default avatarMark Rutland <>
Cc: AKASHI Takahiro <>
Cc: Geoff Levand <>
Acked-by: default avatarArd Biesheuvel <>
Acked-by: default avatarCatalin Marinas <>
Acked-by: default avatarLorenzo Pieralisi <>
Acked-by: default avatarMarc Zyngier <>
Acked-by: default avatarWill Deacon <>
Signed-off-by: default avatarCatalin Marinas <>
parent e8557d1f
......@@ -40,10 +40,6 @@
* the implementation assumes non-aliasing VIPT D-cache and (aliasing)
* VIPT or ASID-tagged VIVT I-cache.
* flush_cache_all()
* Unconditionally clean and invalidate the entire cache.
* flush_cache_mm(mm)
* Clean and invalidate all user space cache entries
......@@ -69,7 +65,6 @@
* - kaddr - page address
* - size - region size
extern void flush_cache_all(void);
extern void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end);
extern void flush_icache_range(unsigned long start, unsigned long end);
extern void __flush_dcache_area(void *addr, size_t len);
......@@ -28,12 +28,8 @@
struct mm_struct;
struct cpu_suspend_ctx;
extern void cpu_cache_off(void);
extern void cpu_do_idle(void);
extern void cpu_do_switch_mm(unsigned long pgd_phys, struct mm_struct *mm);
extern void cpu_reset(unsigned long addr) __attribute__((noreturn));
void cpu_soft_restart(phys_addr_t cpu_reset,
unsigned long addr) __attribute__((noreturn));
extern void cpu_do_suspend(struct cpu_suspend_ctx *ptr);
extern u64 cpu_do_resume(phys_addr_t ptr, u64 idmap_ttbr);
......@@ -41,7 +41,6 @@ struct mm_struct;
extern void show_pte(struct mm_struct *mm, unsigned long addr);
extern void __show_regs(struct pt_regs *);
void soft_restart(unsigned long);
extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
#define UDBG_UNDEFINED (1 << 0)
......@@ -58,14 +58,6 @@ unsigned long __stack_chk_guard __read_mostly;
void soft_restart(unsigned long addr)
cpu_soft_restart(virt_to_phys(cpu_reset), addr);
/* Should never get here */
* Function pointers to optional machine specific functions
......@@ -136,9 +128,7 @@ void machine_power_off(void)
* Restart requires that the secondary CPUs stop performing any activity
* while the primary CPU resets the system. Systems with a single CPU can
* use soft_restart() as their machine descriptor's .restart hook, since that
* will cause the only available CPU to reset. Systems with multiple CPUs must
* while the primary CPU resets the system. Systems with multiple CPUs must
* provide a HW restart implementation, to ensure that all CPUs reset at once.
* This is required so that any code running after reset on the primary CPU
* doesn't have to co-ordinate with other CPUs to ensure they aren't still
......@@ -26,79 +26,6 @@
#include "proc-macros.S"
* __flush_dcache_all()
* Flush the whole D-cache.
* Corrupted registers: x0-x7, x9-x11
dmb sy // ensure ordering with previous memory accesses
mrs x0, clidr_el1 // read clidr
and x3, x0, #0x7000000 // extract loc from clidr
lsr x3, x3, #23 // left align loc bit field
cbz x3, finished // if loc is 0, then no need to clean
mov x10, #0 // start clean at cache level 0
add x2, x10, x10, lsr #1 // work out 3x current cache level
lsr x1, x0, x2 // extract cache type bits from clidr
and x1, x1, #7 // mask of the bits for current cache only
cmp x1, #2 // see what cache we have at this level skip // skip if no cache, or just i-cache
save_and_disable_irqs x9 // make CSSELR and CCSIDR access atomic
msr csselr_el1, x10 // select current cache level in csselr
isb // isb to sych the new cssr&csidr
mrs x1, ccsidr_el1 // read the new ccsidr
restore_irqs x9
and x2, x1, #7 // extract the length of the cache lines
add x2, x2, #4 // add 4 (line length offset)
mov x4, #0x3ff
and x4, x4, x1, lsr #3 // find maximum number on the way size
clz w5, w4 // find bit position of way size increment
mov x7, #0x7fff
and x7, x7, x1, lsr #13 // extract max number of the index size
mov x9, x4 // create working copy of max way size
lsl x6, x9, x5
orr x11, x10, x6 // factor way and cache number into x11
lsl x6, x7, x2
orr x11, x11, x6 // factor index number into x11
dc cisw, x11 // clean & invalidate by set/way
subs x9, x9, #1 // decrement the way loop3
subs x7, x7, #1 // decrement the index loop2
add x10, x10, #2 // increment cache number
cmp x3, x10 loop1
mov x10, #0 // swith back to cache level 0
msr csselr_el1, x10 // select current cache level in csselr
dsb sy
* flush_cache_all()
* Flush the entire cache system. The data cache flush is now achieved
* using atomic clean / invalidates working outwards from L1 cache. This
* is done using Set/Way based cache maintainance instructions. The
* instruction cache can still be invalidated back to the point of
* unification in a single instruction.
mov x12, lr
bl __flush_dcache_all
mov x0, #0
ic ialluis // I+BTB cache invalidate
ret x12
* flush_icache_range(start,end)
......@@ -102,7 +102,6 @@ EXPORT_SYMBOL(flush_dcache_page);
* Additional functions defined in assembly.
......@@ -45,52 +45,6 @@
#define MAIR(attr, mt) ((attr) << ((mt) * 8))
* cpu_cache_off()
* Turn the CPU D-cache off.
mrs x0, sctlr_el1
bic x0, x0, #1 << 2 // clear SCTLR.C
msr sctlr_el1, x0
* cpu_reset(loc)
* Perform a soft reset of the system. Put the CPU into the same state
* as it would be if it had been reset, and branch to what would be the
* reset vector. It must be executed with the flat identity mapping.
* - loc - location to jump to for soft reset
.align 5
mrs x1, sctlr_el1
bic x1, x1, #1
msr sctlr_el1, x1 // disable the MMU
ret x0
/* Save address of cpu_reset() and reset address */
mov x19, x0
mov x20, x1
/* Turn D-cache off */
bl cpu_cache_off
/* Push out all dirty data, and ensure cache is empty */
bl flush_cache_all
mov x0, x20
ret x19
* cpu_do_idle()
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