Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * Xen hypercall batching.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Xen allows multiple hypercalls to be issued at once, using the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  * multicall interface.  This allows the cost of trapping into the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  * hypervisor to be amortized over several calls.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  * This file implements a simple interface for multicalls.  There's a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  * per-cpu buffer of outstanding multicalls.  When you want to queue a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11)  * multicall for issuing, you can allocate a multicall slot for the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  * call and its arguments, along with storage for space which is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  * pointed to by the arguments (for passing pointers to structures,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  * etc).  When the multicall is actually issued, all the space for the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  * commands and allocated memory is freed for reuse.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17)  * Multicalls are flushed whenever any of the buffers get full, or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18)  * when explicitly requested.  There's no way to get per-multicall
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19)  * return results back.  It will BUG if any of the multicalls fail.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #include <linux/percpu.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) #include <linux/hardirq.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) #include <linux/debugfs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) #include <asm/xen/hypercall.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) #include "multicalls.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) #include "debugfs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) #define MC_BATCH	32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) #define MC_DEBUG	0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) #define MC_ARGS		(MC_BATCH * 16)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) struct mc_buffer {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 	unsigned mcidx, argidx, cbidx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 	struct multicall_entry entries[MC_BATCH];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) #if MC_DEBUG
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	struct multicall_entry debug[MC_BATCH];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	void *caller[MC_BATCH];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	unsigned char args[MC_ARGS];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	struct callback {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 		void (*fn)(void *);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 		void *data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	} callbacks[MC_BATCH];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) static DEFINE_PER_CPU(struct mc_buffer, mc_buffer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) DEFINE_PER_CPU(unsigned long, xen_mc_irq_flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) void xen_mc_flush(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	struct mc_buffer *b = this_cpu_ptr(&mc_buffer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	struct multicall_entry *mc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	int ret = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 	unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 	int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	BUG_ON(preemptible());
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	/* Disable interrupts in case someone comes in and queues
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	   something in the middle */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	local_irq_save(flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	trace_xen_mc_flush(b->mcidx, b->argidx, b->cbidx);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) #if MC_DEBUG
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	memcpy(b->debug, b->entries,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 	       b->mcidx * sizeof(struct multicall_entry));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	switch (b->mcidx) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	case 0:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 		/* no-op */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 		BUG_ON(b->argidx != 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 	case 1:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 		/* Singleton multicall - bypass multicall machinery
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 		   and just do the call directly. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 		mc = &b->entries[0];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 		mc->result = xen_single_call(mc->op, mc->args[0], mc->args[1],
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 					     mc->args[2], mc->args[3],
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 					     mc->args[4]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 		ret = mc->result < 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 		if (HYPERVISOR_multicall(b->entries, b->mcidx) != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 			BUG();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 		for (i = 0; i < b->mcidx; i++)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 			if (b->entries[i].result < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 				ret++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	if (WARN_ON(ret)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 		pr_err("%d of %d multicall(s) failed: cpu %d\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 		       ret, b->mcidx, smp_processor_id());
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 		for (i = 0; i < b->mcidx; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 			if (b->entries[i].result < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) #if MC_DEBUG
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 				pr_err("  call %2d: op=%lu arg=[%lx] result=%ld\t%pS\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 				       i + 1,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 				       b->debug[i].op,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 				       b->debug[i].args[0],
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 				       b->entries[i].result,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 				       b->caller[i]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) #else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 				pr_err("  call %2d: op=%lu arg=[%lx] result=%ld\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 				       i + 1,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 				       b->entries[i].op,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 				       b->entries[i].args[0],
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 				       b->entries[i].result);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	b->mcidx = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	b->argidx = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	for (i = 0; i < b->cbidx; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 		struct callback *cb = &b->callbacks[i];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 		(*cb->fn)(cb->data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	b->cbidx = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	local_irq_restore(flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) struct multicall_space __xen_mc_entry(size_t args)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	struct mc_buffer *b = this_cpu_ptr(&mc_buffer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	struct multicall_space ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	unsigned argidx = roundup(b->argidx, sizeof(u64));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	trace_xen_mc_entry_alloc(args);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	BUG_ON(preemptible());
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	BUG_ON(b->argidx >= MC_ARGS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 	if (unlikely(b->mcidx == MC_BATCH ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 		     (argidx + args) >= MC_ARGS)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 		trace_xen_mc_flush_reason((b->mcidx == MC_BATCH) ?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 					  XEN_MC_FL_BATCH : XEN_MC_FL_ARGS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 		xen_mc_flush();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 		argidx = roundup(b->argidx, sizeof(u64));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	ret.mc = &b->entries[b->mcidx];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) #if MC_DEBUG
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	b->caller[b->mcidx] = __builtin_return_address(0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	b->mcidx++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	ret.args = &b->args[argidx];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	b->argidx = argidx + args;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	BUG_ON(b->argidx >= MC_ARGS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) struct multicall_space xen_mc_extend_args(unsigned long op, size_t size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	struct mc_buffer *b = this_cpu_ptr(&mc_buffer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	struct multicall_space ret = { NULL, NULL };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	BUG_ON(preemptible());
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	BUG_ON(b->argidx >= MC_ARGS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	if (unlikely(b->mcidx == 0 ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 		     b->entries[b->mcidx - 1].op != op)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 		trace_xen_mc_extend_args(op, size, XEN_MC_XE_BAD_OP);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 	if (unlikely((b->argidx + size) >= MC_ARGS)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 		trace_xen_mc_extend_args(op, size, XEN_MC_XE_NO_SPACE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	ret.mc = &b->entries[b->mcidx - 1];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	ret.args = &b->args[b->argidx];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 	b->argidx += size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	BUG_ON(b->argidx >= MC_ARGS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	trace_xen_mc_extend_args(op, size, XEN_MC_XE_OK);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) void xen_mc_callback(void (*fn)(void *), void *data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	struct mc_buffer *b = this_cpu_ptr(&mc_buffer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	struct callback *cb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	if (b->cbidx == MC_BATCH) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 		trace_xen_mc_flush_reason(XEN_MC_FL_CALLBACK);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 		xen_mc_flush();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	trace_xen_mc_callback(fn, data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	cb = &b->callbacks[b->cbidx++];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 	cb->fn = fn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	cb->data = data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) }