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Subject: why it not write those 6bits to entrylo0/1 register?
From:	figo zhang <figo1802@gmail.com>
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hi, all,
i have a qusetion , in arch/mips/mm/tlb-r4k.c, __update_tlb() function:
 321<http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/mips/mm/tlb-r4k.c;h=d73428b18b0a41da13e81c64021e62505200ff2d;hb=317c68c04d53198f38314d29ba28b8fc632eccab#l321>#if
defined(CONFIG_64BIT_PHYS_ADDR) && defined(CONFIG_CPU_MIPS32)
322<http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/mips/mm/tlb-r4k.c;h=d73428b18b0a41da13e81c64021e62505200ff2d;hb=317c68c04d53198f38314d29ba28b8fc632eccab#l322>
               write_c0_entrylo0(ptep->pte_high);
323<http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/mips/mm/tlb-r4k.c;h=d73428b18b0a41da13e81c64021e62505200ff2d;hb=317c68c04d53198f38314d29ba28b8fc632eccab#l323>
               ptep++;
324<http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/mips/mm/tlb-r4k.c;h=d73428b18b0a41da13e81c64021e62505200ff2d;hb=317c68c04d53198f38314d29ba28b8fc632eccab#l324>
               write_c0_entrylo1(ptep->pte_high);
325<http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/mips/mm/tlb-r4k.c;h=d73428b18b0a41da13e81c64021e62505200ff2d;hb=317c68c04d53198f38314d29ba28b8fc632eccab#l325>#else
326<http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/mips/mm/tlb-r4k.c;h=d73428b18b0a41da13e81c64021e62505200ff2d;hb=317c68c04d53198f38314d29ba28b8fc632eccab#l326>
               write_c0_entrylo0(pte_val(*ptep++) >> 6);
327<http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/mips/mm/tlb-r4k.c;h=d73428b18b0a41da13e81c64021e62505200ff2d;hb=317c68c04d53198f38314d29ba28b8fc632eccab#l327>
               write_c0_entrylo1(pte_val(*ptep) >> 6);
328<http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=arch/mips/mm/tlb-r4k.c;h=d73428b18b0a41da13e81c64021e62505200ff2d;hb=317c68c04d53198f38314d29ba28b8fc632eccab#l328>#endif

why this right shift 6 bits? this 6 bits contain some important bit, such
as:
C: [bit3~5]: cohereny attribute of page
D:
V:
G:

and how the kernel write the this 6 bit to entrylo0/1 register?

Best,
Figo.zhang

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<div>hi, all,</div>
<div>i have a qusetion , in arch/mips/mm/tlb-r4k.c, __update_tlb() function=
:</div>
<div>
<div class=3D"pre"><a class=3D"linenr" id=3D"l321" href=3D"http://git.kerne=
l.org/?p=3Dlinux/kernel/git/torvalds/linux-2.6.git;a=3Dblob;f=3Darch/mips/m=
m/tlb-r4k.c;h=3Dd73428b18b0a41da13e81c64021e62505200ff2d;hb=3D317c68c04d531=
98f38314d29ba28b8fc632eccab#l321">321</a> #if=A0defined(CONFIG_64BIT_PHYS_A=
DDR)=A0&amp;&amp;=A0defined(CONFIG_CPU_MIPS32)</div>

<div class=3D"pre"><a class=3D"linenr" id=3D"l322" href=3D"http://git.kerne=
l.org/?p=3Dlinux/kernel/git/torvalds/linux-2.6.git;a=3Dblob;f=3Darch/mips/m=
m/tlb-r4k.c;h=3Dd73428b18b0a41da13e81c64021e62505200ff2d;hb=3D317c68c04d531=
98f38314d29ba28b8fc632eccab#l322">322</a> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0write_c0_entrylo0(ptep-&gt;pte_high);</div>

<div class=3D"pre"><a class=3D"linenr" id=3D"l323" href=3D"http://git.kerne=
l.org/?p=3Dlinux/kernel/git/torvalds/linux-2.6.git;a=3Dblob;f=3Darch/mips/m=
m/tlb-r4k.c;h=3Dd73428b18b0a41da13e81c64021e62505200ff2d;hb=3D317c68c04d531=
98f38314d29ba28b8fc632eccab#l323">323</a> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0ptep++;</div>

<div class=3D"pre"><a class=3D"linenr" id=3D"l324" href=3D"http://git.kerne=
l.org/?p=3Dlinux/kernel/git/torvalds/linux-2.6.git;a=3Dblob;f=3Darch/mips/m=
m/tlb-r4k.c;h=3Dd73428b18b0a41da13e81c64021e62505200ff2d;hb=3D317c68c04d531=
98f38314d29ba28b8fc632eccab#l324">324</a> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0write_c0_entrylo1(ptep-&gt;pte_high);</div>

<div class=3D"pre"><a class=3D"linenr" id=3D"l325" href=3D"http://git.kerne=
l.org/?p=3Dlinux/kernel/git/torvalds/linux-2.6.git;a=3Dblob;f=3Darch/mips/m=
m/tlb-r4k.c;h=3Dd73428b18b0a41da13e81c64021e62505200ff2d;hb=3D317c68c04d531=
98f38314d29ba28b8fc632eccab#l325">325</a> #else</div>

<div class=3D"pre"><a class=3D"linenr" id=3D"l326" href=3D"http://git.kerne=
l.org/?p=3Dlinux/kernel/git/torvalds/linux-2.6.git;a=3Dblob;f=3Darch/mips/m=
m/tlb-r4k.c;h=3Dd73428b18b0a41da13e81c64021e62505200ff2d;hb=3D317c68c04d531=
98f38314d29ba28b8fc632eccab#l326">326</a> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0write_c0_entrylo0(pte_val(*ptep++)=A0&gt;&gt;=A06);</div>

<div class=3D"pre"><a class=3D"linenr" id=3D"l327" href=3D"http://git.kerne=
l.org/?p=3Dlinux/kernel/git/torvalds/linux-2.6.git;a=3Dblob;f=3Darch/mips/m=
m/tlb-r4k.c;h=3Dd73428b18b0a41da13e81c64021e62505200ff2d;hb=3D317c68c04d531=
98f38314d29ba28b8fc632eccab#l327">327</a> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0write_c0_entrylo1(pte_val(*ptep)=A0&gt;&gt;=A06);</div>

<div class=3D"pre"><a class=3D"linenr" id=3D"l328" href=3D"http://git.kerne=
l.org/?p=3Dlinux/kernel/git/torvalds/linux-2.6.git;a=3Dblob;f=3Darch/mips/m=
m/tlb-r4k.c;h=3Dd73428b18b0a41da13e81c64021e62505200ff2d;hb=3D317c68c04d531=
98f38314d29ba28b8fc632eccab#l328">328</a> #endif</div>

<div class=3D"pre">=A0</div>
<div class=3D"pre">why this right shift 6 bits? this 6 bits contain some im=
portant bit, such as:</div>
<div class=3D"pre">C: [bit3~5]: cohereny attribute of page</div>
<div class=3D"pre">D:</div>
<div class=3D"pre">V:</div>
<div class=3D"pre">G:</div></div>
<div>=A0</div>
<div>and how the kernel write the this 6 bit to entrylo0/1 register?</div>
<div>=A0</div>
<div>Best,</div>
<div>Figo.zhang</div>

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