locking/atomics, EDAC/altera: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle comments, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts the Altera EDAC code and comments to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Thor Thayer <thor.thayer@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-2-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -175,11 +175,11 @@ static ssize_t altr_sdr_mc_err_inject_write(struct file *file,
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/*
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* To trigger the error, we need to read the data back
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* (the data was written with errors above).
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* The ACCESS_ONCE macros and printk are used to prevent the
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* The READ_ONCE macros and printk are used to prevent the
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* the compiler optimizing these reads out.
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*/
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reg = ACCESS_ONCE(ptemp[0]);
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read_reg = ACCESS_ONCE(ptemp[1]);
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reg = READ_ONCE(ptemp[0]);
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read_reg = READ_ONCE(ptemp[1]);
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/* Force Read */
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rmb();
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@ -618,7 +618,7 @@ static ssize_t altr_edac_device_trig(struct file *file,
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for (i = 0; i < (priv->trig_alloc_sz / sizeof(*ptemp)); i++) {
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/* Read data so we're in the correct state */
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rmb();
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if (ACCESS_ONCE(ptemp[i]))
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if (READ_ONCE(ptemp[i]))
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result = -1;
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/* Toggle Error bit (it is latched), leave ECC enabled */
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writel(error_mask, (drvdata->base + priv->set_err_ofst));
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@ -635,7 +635,7 @@ static ssize_t altr_edac_device_trig(struct file *file,
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/* Read out written data. ECC error caused here */
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for (i = 0; i < ALTR_TRIGGER_READ_WRD_CNT; i++)
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if (ACCESS_ONCE(ptemp[i]) != i)
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if (READ_ONCE(ptemp[i]) != i)
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edac_printk(KERN_ERR, EDAC_DEVICE,
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"Read doesn't match written data\n");
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