[SPARC64]: Eliminate NR_CPUS limitations.
Cheetah systems can have cpuids as large as 1023, although physical systems don't have that many cpus. Only three limitations existed in the kernel preventing arbitrary NR_CPUS values: 1) dcache dirty cpu state stored in page->flags on D-cache aliasing platforms. With some build time calculations and some build-time BUG checks on page->flags layout, this one was easily solved. 2) The cheetah XCALL delivery code could only handle a cpumask with up to 32 cpus set. Some simple looping logic clears that up too. 3) thread_info->cpu was a u8, easily changed to a u16. There are a few spots in the kernel that still put NR_CPUS sized arrays on the kernel stack, but that's not a sparc64 specific problem. Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -147,10 +147,10 @@ config SMP
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If you don't know what to do here, say N.
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config NR_CPUS
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int "Maximum number of CPUs (2-64)"
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range 2 64
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int "Maximum number of CPUs (2-1024)"
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range 2 1024
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depends on SMP
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default "32"
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default "64"
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source "drivers/cpufreq/Kconfig"
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@ -523,7 +523,7 @@ tlb_fixup_done:
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#else
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mov 0, %o0
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#endif
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stb %o0, [%g6 + TI_CPU]
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sth %o0, [%g6 + TI_CPU]
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/* Off we go.... */
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call start_kernel
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@ -400,7 +400,7 @@ static __inline__ void spitfire_xcall_deliver(u64 data0, u64 data1, u64 data2, c
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static void cheetah_xcall_deliver(u64 data0, u64 data1, u64 data2, cpumask_t mask)
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{
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u64 pstate, ver;
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int nack_busy_id, is_jbus;
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int nack_busy_id, is_jbus, need_more;
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if (cpus_empty(mask))
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return;
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@ -416,6 +416,7 @@ static void cheetah_xcall_deliver(u64 data0, u64 data1, u64 data2, cpumask_t mas
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__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
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retry:
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need_more = 0;
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__asm__ __volatile__("wrpr %0, %1, %%pstate\n\t"
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: : "r" (pstate), "i" (PSTATE_IE));
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@ -444,6 +445,10 @@ retry:
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: /* no outputs */
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: "r" (target), "i" (ASI_INTR_W));
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nack_busy_id++;
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if (nack_busy_id == 32) {
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need_more = 1;
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break;
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}
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}
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}
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@ -460,6 +465,16 @@ retry:
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if (dispatch_stat == 0UL) {
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__asm__ __volatile__("wrpr %0, 0x0, %%pstate"
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: : "r" (pstate));
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if (unlikely(need_more)) {
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int i, cnt = 0;
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for_each_cpu_mask(i, mask) {
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cpu_clear(i, mask);
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cnt++;
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if (cnt == 32)
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break;
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}
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goto retry;
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}
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return;
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}
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if (!--stuck)
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@ -497,6 +512,8 @@ retry:
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if ((dispatch_stat & check_mask) == 0)
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cpu_clear(i, mask);
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this_busy_nack += 2;
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if (this_busy_nack == 64)
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break;
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}
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goto retry;
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@ -191,12 +191,9 @@ inline void flush_dcache_page_impl(struct page *page)
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}
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#define PG_dcache_dirty PG_arch_1
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#define PG_dcache_cpu_shift 24UL
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#define PG_dcache_cpu_mask (256UL - 1UL)
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#if NR_CPUS > 256
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#error D-cache dirty tracking and thread_info->cpu need fixing for > 256 cpus
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#endif
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#define PG_dcache_cpu_shift 32UL
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#define PG_dcache_cpu_mask \
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((1UL<<ilog2(roundup_pow_of_two(NR_CPUS)))-1UL)
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#define dcache_dirty_cpu(page) \
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(((page)->flags >> PG_dcache_cpu_shift) & PG_dcache_cpu_mask)
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@ -1349,6 +1346,19 @@ void __init paging_init(void)
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unsigned long end_pfn, pages_avail, shift, phys_base;
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unsigned long real_end, i;
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/* These build time checkes make sure that the dcache_dirty_cpu()
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* page->flags usage will work.
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*
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* When a page gets marked as dcache-dirty, we store the
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* cpu number starting at bit 32 in the page->flags. Also,
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* functions like clear_dcache_dirty_cpu use the cpu mask
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* in 13-bit signed-immediate instruction fields.
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*/
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BUILD_BUG_ON(FLAGS_RESERVED != 32);
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BUILD_BUG_ON(SECTIONS_WIDTH + NODES_WIDTH + ZONES_WIDTH +
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ilog2(roundup_pow_of_two(NR_CPUS)) > FLAGS_RESERVED);
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BUILD_BUG_ON(NR_CPUS > 4096);
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kern_base = (prom_boot_mapping_phys_low >> 22UL) << 22UL;
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kern_size = (unsigned long)&_end - (unsigned long)KERNBASE;
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@ -202,7 +202,7 @@ extern struct sun4v_2insn_patch_entry __sun4v_2insn_patch,
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* the calculations done by the macro mid-stream.
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*/
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#define LOAD_PER_CPU_BASE(DEST, THR, REG1, REG2, REG3) \
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ldub [THR + TI_CPU], REG1; \
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lduh [THR + TI_CPU], REG1; \
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sethi %hi(__per_cpu_shift), REG3; \
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sethi %hi(__per_cpu_base), REG2; \
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ldx [REG3 + %lo(__per_cpu_shift)], REG3; \
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@ -38,8 +38,8 @@ struct thread_info {
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/* D$ line 1 */
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struct task_struct *task;
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unsigned long flags;
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__u8 cpu;
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__u8 fpsaved[7];
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__u8 pad;
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unsigned long ksp;
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/* D$ line 2 */
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@ -49,7 +49,7 @@ struct thread_info {
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int preempt_count; /* 0 => preemptable, <0 => BUG */
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__u8 new_child;
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__u8 syscall_noerror;
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__u16 __pad;
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__u16 cpu;
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unsigned long *utraps;
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@ -83,8 +83,7 @@ struct thread_info {
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#define TI_CURRENT_DS (TI_FLAGS + TI_FLAG_BYTE_CURRENT_DS)
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#define TI_FPDEPTH (TI_FLAGS + TI_FLAG_BYTE_FPDEPTH)
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#define TI_WSAVED (TI_FLAGS + TI_FLAG_BYTE_WSAVED)
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#define TI_CPU 0x00000010
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#define TI_FPSAVED 0x00000011
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#define TI_FPSAVED 0x00000010
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#define TI_KSP 0x00000018
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#define TI_FAULT_ADDR 0x00000020
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#define TI_KREGS 0x00000028
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@ -92,6 +91,7 @@ struct thread_info {
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#define TI_PRE_COUNT 0x00000038
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#define TI_NEW_CHILD 0x0000003c
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#define TI_SYS_NOERROR 0x0000003d
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#define TI_CPU 0x0000003e
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#define TI_UTRAPS 0x00000040
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#define TI_REG_WINDOW 0x00000048
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#define TI_RWIN_SPTRS 0x000003c8
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