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08273c9f61
With the tokens for all implemented RTAS functions now available via rtas_function_token(), which is optimal and safe for arbitrary contexts, there is no need to use rtas_token() or cache its result. Most conversions are trivial, but a few are worth describing in more detail: * Error injection token comparisons for lockdown purposes are consolidated into a simple predicate: token_is_restricted_errinjct(). * A couple of special cases in block_rtas_call() do not use rtas_token() but perform string comparisons against names in the function table. These are converted to compare against token values instead, which is logically equivalent but less expensive. * The lookup for the ibm,os-term token can be deferred until needed, instead of caching it at boot to avoid device tree traversal during panic. * Since rtas_function_token() accesses a read-only data structure without taking any locks, xmon's lookup of set-indicator can be performed as needed instead of cached at startup. Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-20-26929c8cce78@linux.ibm.com
95 lines
2.2 KiB
C
95 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* c 2001 PPC 64 Team, IBM Corp
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*
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* /dev/nvram driver for PPC
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/uaccess.h>
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#include <linux/of.h>
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#include <asm/machdep.h>
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#include <asm/rtas.h>
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#include "chrp.h"
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static unsigned int nvram_size;
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static unsigned char nvram_buf[4];
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static DEFINE_SPINLOCK(nvram_lock);
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static unsigned char chrp_nvram_read_val(int addr)
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{
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unsigned int done;
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unsigned long flags;
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unsigned char ret;
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if (addr >= nvram_size) {
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printk(KERN_DEBUG "%s: read addr %d > nvram_size %u\n",
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current->comm, addr, nvram_size);
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return 0xff;
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}
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spin_lock_irqsave(&nvram_lock, flags);
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if ((rtas_call(rtas_function_token(RTAS_FN_NVRAM_FETCH), 3, 2, &done, addr,
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__pa(nvram_buf), 1) != 0) || 1 != done)
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ret = 0xff;
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else
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ret = nvram_buf[0];
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spin_unlock_irqrestore(&nvram_lock, flags);
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return ret;
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}
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static void chrp_nvram_write_val(int addr, unsigned char val)
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{
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unsigned int done;
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unsigned long flags;
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if (addr >= nvram_size) {
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printk(KERN_DEBUG "%s: write addr %d > nvram_size %u\n",
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current->comm, addr, nvram_size);
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return;
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}
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spin_lock_irqsave(&nvram_lock, flags);
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nvram_buf[0] = val;
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if ((rtas_call(rtas_function_token(RTAS_FN_NVRAM_STORE), 3, 2, &done, addr,
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__pa(nvram_buf), 1) != 0) || 1 != done)
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printk(KERN_DEBUG "rtas IO error storing 0x%02x at %d", val, addr);
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spin_unlock_irqrestore(&nvram_lock, flags);
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}
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static ssize_t chrp_nvram_size(void)
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{
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return nvram_size;
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}
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void __init chrp_nvram_init(void)
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{
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struct device_node *nvram;
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const __be32 *nbytes_p;
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unsigned int proplen;
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nvram = of_find_node_by_type(NULL, "nvram");
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if (nvram == NULL)
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return;
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nbytes_p = of_get_property(nvram, "#bytes", &proplen);
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if (nbytes_p == NULL || proplen != sizeof(unsigned int)) {
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of_node_put(nvram);
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return;
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}
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nvram_size = be32_to_cpup(nbytes_p);
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printk(KERN_INFO "CHRP nvram contains %u bytes\n", nvram_size);
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of_node_put(nvram);
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ppc_md.nvram_read_val = chrp_nvram_read_val;
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ppc_md.nvram_write_val = chrp_nvram_write_val;
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ppc_md.nvram_size = chrp_nvram_size;
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return;
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}
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MODULE_LICENSE("GPL v2");
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